docs/gitea-execution-profiles.md

@@ -252,6 +252,26 @@ the "one server per trust boundary" model described in
 [`tool-boundaries.md`](tool-boundaries.md) and
 [`credential-isolation.md`](credential-isolation.md).
 
+## Profile Activation and Runtime Identity Clarity (#131)
+
+To make Gitea MCP profile activation and runtime identity state explicit, the following mechanisms are supported:
+
+### 1. Static-Profile vs. Dynamic-Profile Mode
+- **Static-Profile Mode (Default):** The active profile is fixed at server launch based on the `GITEA_MCP_PROFILE` environment variable (with `GITEA_MCP_CONFIG` pointing to the config path). Local environment variables are static once a subprocess is spawned by the host. Modifying the environment variables on the host does not dynamically update an already-connected MCP server process.
+- **Dynamic-Profile Mode:** Profile switching via the `gitea_activate_profile` tool is supported **only** if the configuration JSON explicitly opts in by setting `"allow_runtime_switching": true` under rules or top-level keys. Otherwise, attempting to switch profiles dynamically will fail closed.
+
+### 2. Dual MCP Namespaces Recommendation
+For security-sensitive or high-risk tasks, the preferred safety model uses separate, isolated MCP server instances (namespaces/sessions) launched with static profiles:
+- `gitea-author`: Exposes tools configured with author permissions; cannot perform approvals or merges.
+- `gitea-reviewer`: Exposes tools configured with reviewer permissions; used for PR reviews and merges.
+This layout maintains physical separation of credentials and prevents privilege escalation within a single session.
+
+### 3. Verification Post-Switching
+When dynamic profile switching is enabled and a profile is activated via `gitea_activate_profile`, the session MUST immediately:
+1. Clear the cached identity.
+2. Call `gitea_whoami` with the target remote to prove and verify the fresh Gitea authenticated identity.
+This guarantees the active profile operations align with the actual Gitea authenticated user credential.
+
 ## Relationship to roadmap issues
 
 This document defines the **model only**. Related work is tracked separately

gitea_config.py

@@ -192,11 +192,32 @@ def config_path():
     return (os.environ.get(ENV_CONFIG_PATH) or "").strip() or None
 
 
+_active_profile_override = None
+
+
 def selected_profile_name():
     """Return the selected profile name from the environment, or None."""
+    if _active_profile_override is not None:
+        return _active_profile_override
     return (os.environ.get(ENV_PROFILE) or "").strip() or None
 
 
+def is_runtime_switching_enabled(path=None):
+    """Check if runtime profile switching is explicitly enabled in config."""
+    try:
+        config = load_config(path)
+    except Exception:
+        return False
+    if not config:
+        return False
+    rules = config.get("rules") or {}
+    if rules.get("allow_runtime_switching") is True:
+        return True
+    if config.get("allow_runtime_switching") is True:
+        return True
+    return False
+
+
 def load_config(path=None):
     """Load and minimally validate the canonical JSON config.
 

mcp_server.py

@@ -597,6 +597,83 @@ def gitea_check_pr_eligibility(
     result["eligible"] = len(reasons) == 0
     if result["eligible"]:
         reasons.append("all eligibility checks passed")
+
+    # Add enhanced error clarity details (#131)
+    auth_user = result["authenticated_user"]
+    pr_author = result["pr_author"]
+    profile_name = result["profile_name"]
+    is_self = bool(auth_user and pr_author and auth_user == pr_author)
+
+    result["active_identity"] = auth_user
+    result["active_profile"] = profile_name
+    result["self_author"] = is_self
+
+    # Determine missing permission
+    missing_perm = None
+    if not op_ok:
+        missing_perm = f"gitea.pr.{action}" if action in ("approve", "request_changes", "merge") else f"gitea.{action}"
+
+    result["missing_permission"] = missing_perm
+
+    # Determine required profile
+    req_profile = None
+    if action in ("approve", "request_changes", "review"):
+        req_profile = "A profile with reviewer role permissions (allowing approve/merge/review, and forbidding author operations)"
+    elif action == "merge":
+        req_profile = "A profile with reviewer role permissions and explicit merge permission"
+    result["required_profile"] = req_profile
+
+    # Determine required identity
+    req_identity = None
+    if is_self:
+        req_identity = f"Any Gitea user other than PR author '{pr_author}'"
+    result["required_identity"] = req_identity
+
+    # Determine if fixable by profile switch vs requires different namespace
+    switching_supported = gitea_config.is_runtime_switching_enabled()
+    fixable_by_switch = False
+    req_different_ns = False
+
+    if not op_ok:
+        config = gitea_config.load_config()
+        has_capable_profile = False
+        if config:
+            for name, p in (config.get("profiles") or {}).items():
+                p_allowed = p.get("allowed_operations", [])
+                p_forbidden = p.get("forbidden_operations", [])
+                ok, _ = gitea_config.check_operation(action, p_allowed, p_forbidden)
+                if ok:
+                    has_capable_profile = True
+                    break
+        if switching_supported and has_capable_profile:
+            fixable_by_switch = True
+        else:
+            req_different_ns = True
+
+    result["fixable_by_profile_switch"] = fixable_by_switch
+    result["requires_different_namespace"] = req_different_ns
+
+    # Determine safe next step
+    safe_step = "Ready."
+    if not result["eligible"]:
+        if is_self:
+            safe_step = "Self-review/self-merge is forbidden. Ask a different operator/reviewer to review and merge this PR."
+        elif not auth_user:
+            safe_step = f"Ask the operator to configure valid credentials/token for profile '{profile_name}'."
+        elif not op_ok:
+            if fixable_by_switch:
+                safe_step = f"Switch to a reviewer profile by calling gitea_activate_profile with a profile that allows {action}."
+            else:
+                safe_step = "Switch to the reviewer MCP session (e.g. gitea-reviewer) which has reviewer permissions configured, or ask the operator to update GITEA_MCP_PROFILE to a reviewer profile."
+        elif result["pr_state"] != "open":
+            safe_step = "No action can be taken on a closed/merged PR."
+        elif action == "merge":
+            if result["mergeable"] is False:
+                safe_step = "Address conflicts in the PR branches first, or wait for CI checks to pass before merging."
+            elif result["mergeable"] is None:
+                safe_step = "Wait for Gitea to finish calculating mergeability or trigger a re-check."
+
+    result["safe_next_step"] = safe_step
     return result
 
 
@@ -1574,13 +1651,11 @@ _GUIDE_RULES = {
         "(gitea.issue.comment) are gated separately from PR reviews "
         "(gitea.pr.*)."),
     "profile_switching": [
-        "The active profile comes from GITEA_MCP_PROFILE (with "
+        "The active profile is selected via GITEA_MCP_PROFILE (with GITEA_MCP_CONFIG pointing at the config path).",
-        "GITEA_MCP_CONFIG pointing at the profiles config).",
+        "By default, static-profile mode is active: changing local environment variables does not dynamically update the already-connected MCP server process.",
-        "Switching profiles requires changing the launcher environment and "
+        "If runtime profile switching is explicitly enabled in the config (allow_runtime_switching: true), use gitea_activate_profile to switch profiles in-place.",
-        "reconnecting the MCP server (operator action, e.g. /mcp); the "
+        "If switching is disabled, you must change the launcher configuration/environment (dual-namespace) and reconnect/restart the MCP session.",
-        "server process cannot switch identities in place.",
+        "After any profile switch or startup, you must verify the new runtime identity with a fresh gitea_whoami call before taking action."
-        "After any switch, verify with gitea_whoami before doing anything "
-        "else.",
     ],
     "identity_verification": [
         "Call gitea_whoami with an explicit remote first; confirm the "
@@ -1703,10 +1778,12 @@ _PROJECT_SKILLS = {
         "required_operations": [],
         "status": "available",
         "steps": [
-            "Ask the operator to update GITEA_MCP_PROFILE in the launcher "
+            "Check profile mode using gitea_get_runtime_context.",
-            "environment.",
+            "If dynamic-profile mode is enabled (allow_runtime_switching: true), "
-            "Operator reconnects the MCP server (e.g. /mcp).",
+            "call gitea_activate_profile to switch in-place.",
-            "Verify the new identity with gitea_whoami before acting.",
+            "If static-profile mode (default), ask the operator to update GITEA_MCP_PROFILE "
+            "in the launcher environment and reconnect/restart the MCP server.",
+            "Immediately verify the new identity with a fresh gitea_whoami call before taking action.",
             "If identity does not match the expected role, STOP.",
         ],
     },
@@ -2115,6 +2192,306 @@ def gitea_get_profile(
     return result
 
 
+@mcp.tool()
+def gitea_get_runtime_context(
+    remote: str = "dadeschools",
+    host: str | None = None,
+) -> dict:
+    """Read-only: explicit visibility into active profile, configuration model, and eligibility.
+
+    Reports config model shape, profile mode (static vs dynamic), and detailed blocks.
+
+    Args:
+        remote: Known instance — 'dadeschools' or 'prgs'.
+        host: Override the Gitea host.
+    """
+    profile = get_profile()
+    config = gitea_config.load_config()
+    reveal = _reveal_endpoints()
+
+    # Determine config model/version
+    if config is None:
+        config_model = "env-only"
+    elif config.get("version") == 1:
+        config_model = "v1"
+    elif config.get("version") == 2:
+        if "contexts" in config or config.get("shape") == "contexts":
+            config_model = "v2-contexts"
+        else:
+            config_model = "v2-environments"
+    else:
+        config_model = f"unknown-version-{config.get('version')}"
+
+    # Determine profile source
+    if os.environ.get("GITEA_PROFILE_NAME"):
+        profile_source = "env var"
+    elif gitea_config.selected_profile_name():
+        profile_source = "config file profile"
+    else:
+        profile_source = "default"
+
+    h = host or (REMOTES.get(remote, {}).get("host") if remote in REMOTES else None)
+    username = _authenticated_username(h) if h else None
+
+    switching = gitea_config.is_runtime_switching_enabled()
+    profile_mode = "dynamic-profile" if switching else "static-profile"
+
+    # Evaluate review/merge eligibility
+    allowed = profile["allowed_operations"] or []
+    forbidden = profile["forbidden_operations"] or []
+
+    # Check approve
+    approve_ok, _ = gitea_config.check_operation("approve", allowed, forbidden)
+    # Check merge
+    merge_ok, _ = gitea_config.check_operation("merge", allowed, forbidden)
+
+    review_merge_allowed = False
+    blocked_reasons = []
+    suggested_fix = "none"
+
+    if not username:
+        blocked_reasons.append("Authenticated identity is unresolved. Gitea credentials are missing or invalid.")
+        suggested_fix = "operator action"
+    elif not (approve_ok or merge_ok):
+        blocked_reasons.append(
+            f"Active profile '{profile['profile_name']}' does not permit review or merge operations."
+        )
+        if switching:
+            suggested_fix = "profile switch"
+        else:
+            suggested_fix = "reviewer namespace"
+    else:
+        review_merge_allowed = True
+
+    # Note that self-review and self-merge are blocked regardless of profile roles
+    blocked_reasons.append(
+        "Note: self-review and self-merge are always blocked at runtime for any PR authored by the active user."
+    )
+
+    safe_next_action = "None; ready for operations."
+    if suggested_fix == "operator action":
+        safe_next_action = f"Ask the operator to configure valid credentials/token for profile '{profile['profile_name']}'."
+    elif suggested_fix == "profile switch":
+        safe_next_action = "Switch to a reviewer profile by calling gitea_activate_profile with a reviewer profile."
+    elif suggested_fix == "reviewer namespace":
+        safe_next_action = (
+            "Switch to the reviewer MCP session (e.g. gitea-reviewer) which has reviewer permissions configured, "
+            "or ask the operator to update GITEA_MCP_PROFILE to a reviewer profile."
+        )
+
+    result = {
+        "active_profile": profile["profile_name"],
+        "authenticated_username": username,
+        "remote": remote if remote in REMOTES else None,
+        "config_model": config_model,
+        "profile_source": profile_source,
+        "allowed_operations": allowed,
+        "forbidden_operations": forbidden,
+        "runtime_switching_supported": switching,
+        "profile_mode": profile_mode,
+        "review_merge_allowed": review_merge_allowed,
+        "review_merge_blocked_reasons": blocked_reasons,
+        "suggested_fix": suggested_fix,
+        "safe_next_action": safe_next_action,
+    }
+
+    if reveal and h:
+        result["server"] = f"https://{h}"
+
+    return result
+
+
+@mcp.tool()
+def gitea_list_profiles() -> dict:
+    """Read-only: list all Gitea MCP profiles with redacted metadata.
+
+    Exposes names, role kinds, enabled state, allowed/forbidden operations, and active status.
+    Token values, keychain IDs, and raw URLs are hidden unless GITEA_MCP_REVEAL_ENDPOINTS=1 is enabled.
+    """
+    config = gitea_config.load_config()
+    reveal = _reveal_endpoints()
+    active_name = gitea_config.selected_profile_name() or get_profile()["profile_name"]
+
+    profiles_out = []
+
+    if config is None:
+        # Env-only: return the active profile
+        p = get_profile()
+        role = _role_kind(p["allowed_operations"], p["forbidden_operations"])
+        h = REMOTES.get("dadeschools", {}).get("host")  # default host
+        username = _authenticated_username(h) if h else None
+        
+        prof = {
+            "name": p["profile_name"],
+            "role_kind": role,
+            "allowed_operations": p["allowed_operations"],
+            "forbidden_operations": p["forbidden_operations"],
+            "identity_status": "verified" if username else "unresolved",
+            "is_active": True,
+            "enabled": True,
+        }
+        if reveal:
+            prof["token_source_name"] = p["token_source_name"]
+            prof["base_url"] = p["base_url"]
+        profiles_out.append(prof)
+    else:
+        # Load from config profiles
+        profiles_dict = config.get("profiles") or {}
+        unavailable_dict = config.get("unavailable") or {}
+        audit_only_profiles = config.get("audit_only_profiles") or {}
+
+        # First, process available profiles
+        for name, p in profiles_dict.items():
+            role = _role_kind(p.get("allowed_operations", []), p.get("forbidden_operations", []))
+            is_active = (name == active_name)
+            
+            # Identity status lookup
+            if is_active:
+                h = REMOTES.get("dadeschools", {}).get("host")  # default host
+                username = _authenticated_username(h) if h else None
+                identity_status = "verified" if username else "unresolved"
+            else:
+                # Safely resolve if credentials are present without networking
+                try:
+                    tok = gitea_config.resolve_token(p)
+                    identity_status = "credentials present" if tok else "missing credentials"
+                except Exception:
+                    identity_status = "missing credentials"
+
+            prof = {
+                "name": name,
+                "role_kind": role,
+                "allowed_operations": p.get("allowed_operations", []),
+                "forbidden_operations": p.get("forbidden_operations", []),
+                "identity_status": identity_status,
+                "is_active": is_active,
+                "enabled": p.get("enabled", True),
+            }
+            if reveal:
+                if isinstance(p.get("auth"), dict):
+                    prof["auth"] = p["auth"]
+                prof["base_url"] = p.get("base_url")
+            else:
+                if isinstance(p.get("auth"), dict):
+                    prof["auth"] = {k: ("<redacted>" if k != "type" else v) for k, v in p["auth"].items()}
+                prof["base_url"] = "<redacted>"
+            profiles_out.append(prof)
+
+        # Process unavailable/disabled/audit-only profiles
+        for name, p in audit_only_profiles.items():
+            role = _role_kind(p.get("allowed_operations", []), p.get("forbidden_operations", []))
+            is_active = (name == active_name)
+            prof = {
+                "name": name,
+                "role_kind": role,
+                "allowed_operations": p.get("allowed_operations", []),
+                "forbidden_operations": p.get("forbidden_operations", []),
+                "identity_status": "unavailable (disabled)",
+                "is_active": is_active,
+                "enabled": p.get("enabled", True),
+                "unavailable_reason": p.get("_unavailable_reason"),
+            }
+            if reveal:
+                if isinstance(p.get("auth"), dict):
+                    prof["auth"] = p["auth"]
+                prof["base_url"] = p.get("base_url")
+            else:
+                if isinstance(p.get("auth"), dict):
+                    prof["auth"] = {k: ("<redacted>" if k != "type" else v) for k, v in p["auth"].items()}
+                prof["base_url"] = "<redacted>"
+            profiles_out.append(prof)
+
+        # Handle unavailable mappings that are not in audit_only
+        for name, reason in unavailable_dict.items():
+            if not any(x["name"] == name for x in profiles_out):
+                profiles_out.append({
+                    "name": name,
+                    "role_kind": "limited",
+                    "allowed_operations": [],
+                    "forbidden_operations": [],
+                    "identity_status": "unavailable",
+                    "is_active": (name == active_name),
+                    "enabled": False,
+                    "unavailable_reason": reason,
+                })
+
+    return {"profiles": profiles_out}
+
+
+@mcp.tool()
+def gitea_activate_profile(
+    profile_name: str,
+    remote: str = "dadeschools",
+    host: str | None = None,
+) -> dict:
+    """Gated profile activation. Switch the active profile in-place for this runtime session.
+
+    Only allowed if "allow_runtime_switching": true is explicitly configured.
+
+    Args:
+        profile_name: Profile to activate.
+        remote: Known instance — 'dadeschools' or 'prgs'.
+        host: Override the Gitea host.
+    """
+    if not gitea_config.is_runtime_switching_enabled():
+        return {
+            "success": False,
+            "message": (
+                "Runtime profile switching is disabled in this configuration. Static profile mode is active. "
+                "To enable switching, set 'allow_runtime_switching': true in the config rules."
+            )
+        }
+
+    config = gitea_config.load_config()
+    if not config:
+        return {
+            "success": False,
+            "message": "No profiles configuration file is loaded. Switching is not supported in env-only mode."
+        }
+
+    profiles_dict = config.get("profiles") or {}
+    if profile_name not in profiles_dict:
+        return {
+            "success": False,
+            "message": f"Profile '{profile_name}' not found in loaded config."
+        }
+
+    h = host or (REMOTES.get(remote, {}).get("host") if remote in REMOTES else None)
+
+    # 1. Record before state
+    before_profile = get_profile()["profile_name"]
+    before_identity = _authenticated_username(h) if h else None
+
+    # 2. Perform switch
+    gitea_config._active_profile_override = profile_name
+
+    # 3. Clear identity cache to force a fresh verification
+    if h:
+        _IDENTITY_CACHE.pop(h, None)
+    
+    # 4. Resolve fresh identity
+    after_profile = get_profile()["profile_name"]
+    after_identity = _authenticated_username(h) if h else None
+
+    # 5. Audit the switch if auditing is on
+    _audit(
+        "activate_profile",
+        host=h,
+        remote=remote,
+        result={"success": True, "before": before_profile, "after": after_profile},
+        username=after_identity,
+    )
+
+    return {
+        "success": True,
+        "message": f"Successfully activated profile '{profile_name}' (fresh identity verification complete).",
+        "before_profile": before_profile,
+        "before_identity": before_identity,
+        "after_profile": after_profile,
+        "after_identity": after_identity,
+    }
+
+
 @mcp.tool()
 def gitea_audit_config() -> dict:
     """Audit the configured profiles/services: enabled state, no secrets.

tests/test_runtime_clarity.py

@@ -0,0 +1,256 @@
+"""Tests for runtime context, profile activation, profile listing, and enhanced error clarity.
+
+Covers Issue #131 requirements.
+"""
+import os
+import sys
+import json
+import tempfile
+import unittest
+from unittest.mock import patch, MagicMock
+
+sys.path.insert(0, str(__import__("pathlib").Path(__file__).resolve().parent.parent))
+
+import gitea_config
+import gitea_auth
+import mcp_server
+
+CONFIG_SWITCHING_DISABLED = {
+    "version": 2,
+    "contexts": {
+        "ctx": {
+            "enabled": True,
+            "gitea": {
+                "enabled": True,
+                "base_url": "https://gitea.example.com"
+            }
+        }
+    },
+    "profiles": {
+        "author-profile": {
+            "enabled": True,
+            "context": "ctx",
+            "role": "author",
+            "username": "author-user",
+            "auth": {"type": "env", "name": "GITEA_TOKEN_AUTHOR"},
+            "allowed_operations": ["gitea.read", "gitea.pr.create", "gitea.branch.push"],
+            "forbidden_operations": ["gitea.pr.approve", "gitea.pr.merge"],
+            "execution_profile": "author-profile"
+        },
+        "reviewer-profile": {
+            "enabled": True,
+            "context": "ctx",
+            "role": "reviewer",
+            "username": "reviewer-user",
+            "auth": {"type": "env", "name": "GITEA_TOKEN_REVIEWER"},
+            "allowed_operations": ["gitea.read", "gitea.pr.approve", "gitea.pr.merge"],
+            "forbidden_operations": ["gitea.pr.create", "gitea.branch.push"],
+            "execution_profile": "reviewer-profile"
+        }
+    },
+    "rules": {
+        "allow_runtime_switching": False
+    }
+}
+
+CONFIG_SWITCHING_ENABLED = {
+    **CONFIG_SWITCHING_DISABLED,
+    "rules": {
+        "allow_runtime_switching": True
+    }
+}
+
+class TestRuntimeClarity(unittest.TestCase):
+    def setUp(self):
+        self._remotes_patch = patch.dict(mcp_server.REMOTES, {
+            "dadeschools": {"host": "gitea.example.com", "org": "Example-Org", "repo": "Example-Repo"},
+            "prgs": {"host": "gitea.example.com", "org": "Example-Org", "repo": "Example-Repo"}
+        })
+        self._remotes_patch.start()
+        mcp_server._IDENTITY_CACHE.clear()
+        gitea_config._active_profile_override = None
+        self._dir = tempfile.TemporaryDirectory()
+        self.config_path = os.path.join(self._dir.name, "profiles.json")
+        self._write_config(CONFIG_SWITCHING_DISABLED)
+
+    def tearDown(self):
+        self._remotes_patch.stop()
+        mcp_server._IDENTITY_CACHE.clear()
+        gitea_config._active_profile_override = None
+        self._dir.cleanup()
+
+    def _write_config(self, obj):
+        with open(self.config_path, "w", encoding="utf-8") as fh:
+            fh.write(json.dumps(obj))
+
+    def _env(self, profile="author-profile", reveal="0"):
+        return {
+            "GITEA_MCP_CONFIG": self.config_path,
+            "GITEA_MCP_PROFILE": profile,
+            "GITEA_MCP_REVEAL_ENDPOINTS": reveal,
+            "GITEA_TOKEN_AUTHOR": "author-pass",
+            "GITEA_TOKEN_REVIEWER": "reviewer-pass",
+        }
+
+    # -------------------------------------------------------------------------
+    # gitea_get_runtime_context
+    # -------------------------------------------------------------------------
+    @patch("mcp_server.api_request", return_value={"login": "author-user"})
+    @patch("mcp_server.get_auth_header", return_value="token author-pass")
+    def test_get_runtime_context_author(self, _auth, _api):
+        with patch.dict(os.environ, self._env("author-profile"), clear=True):
+            ctx = mcp_server.gitea_get_runtime_context(remote="dadeschools")
+        self.assertEqual(ctx["active_profile"], "author-profile")
+        self.assertEqual(ctx["authenticated_username"], "author-user")
+        self.assertEqual(ctx["config_model"], "v2-contexts")
+        self.assertEqual(ctx["profile_source"], "config file profile")
+        self.assertFalse(ctx["runtime_switching_supported"])
+        self.assertEqual(ctx["profile_mode"], "static-profile")
+        self.assertFalse(ctx["review_merge_allowed"])
+        self.assertEqual(ctx["suggested_fix"], "reviewer namespace")
+        self.assertIn("does not permit review or merge", ctx["review_merge_blocked_reasons"][0])
+        self.assertIn("Switch to the reviewer MCP session", ctx["safe_next_action"])
+
+    @patch("mcp_server.api_request", return_value={"login": "reviewer-user"})
+    @patch("mcp_server.get_auth_header", return_value="token reviewer-pass")
+    def test_get_runtime_context_reviewer(self, _auth, _api):
+        with patch.dict(os.environ, self._env("reviewer-profile"), clear=True):
+            ctx = mcp_server.gitea_get_runtime_context(remote="dadeschools")
+        self.assertEqual(ctx["active_profile"], "reviewer-profile")
+        self.assertEqual(ctx["authenticated_username"], "reviewer-user")
+        self.assertTrue(ctx["review_merge_allowed"])
+        self.assertEqual(ctx["suggested_fix"], "none")
+        self.assertEqual(ctx["safe_next_action"], "None; ready for operations.")
+
+    # -------------------------------------------------------------------------
+    # gitea_list_profiles
+    # -------------------------------------------------------------------------
+    @patch("mcp_server.api_request", return_value={"login": "author-user"})
+    @patch("mcp_server.get_auth_header", return_value="token author-pass")
+    def test_list_profiles_redacted_by_default(self, _auth, _api):
+        with patch.dict(os.environ, self._env("author-profile", reveal="0"), clear=True):
+            res = mcp_server.gitea_list_profiles()
+        profiles = res["profiles"]
+        self.assertEqual(len(profiles), 2)
+        
+        author_prof = next(p for p in profiles if p["name"] == "author-profile")
+        self.assertTrue(author_prof["is_active"])
+        self.assertEqual(author_prof["role_kind"], "author")
+        self.assertEqual(author_prof["auth"]["name"], "<redacted>")
+        self.assertEqual(author_prof["base_url"], "<redacted>")
+        self.assertEqual(author_prof["identity_status"], "verified")
+
+        reviewer_prof = next(p for p in profiles if p["name"] == "reviewer-profile")
+        self.assertFalse(reviewer_prof["is_active"])
+        self.assertEqual(reviewer_prof["role_kind"], "reviewer")
+        self.assertEqual(reviewer_prof["auth"]["name"], "<redacted>")
+        self.assertEqual(reviewer_prof["base_url"], "<redacted>")
+        self.assertEqual(reviewer_prof["identity_status"], "credentials present")
+
+    @patch("mcp_server.api_request", return_value={"login": "author-user"})
+    @patch("mcp_server.get_auth_header", return_value="token author-pass")
+    def test_list_profiles_revealed_under_opt_in(self, _auth, _api):
+        with patch.dict(os.environ, self._env("author-profile", reveal="1"), clear=True):
+            res = mcp_server.gitea_list_profiles()
+        profiles = res["profiles"]
+        
+        author_prof = next(p for p in profiles if p["name"] == "author-profile")
+        self.assertEqual(author_prof["auth"]["name"], "GITEA_TOKEN_AUTHOR")
+        self.assertEqual(author_prof["base_url"], "https://gitea.example.com")
+
+    # -------------------------------------------------------------------------
+    # gitea_activate_profile
+    # -------------------------------------------------------------------------
+    def test_activate_profile_fails_when_disabled(self):
+        self._write_config(CONFIG_SWITCHING_DISABLED)
+        with patch.dict(os.environ, self._env("author-profile"), clear=True):
+            res = mcp_server.gitea_activate_profile(profile_name="reviewer-profile")
+        self.assertFalse(res["success"])
+        self.assertIn("switching is disabled", res["message"].lower())
+        self.assertIsNone(gitea_config._active_profile_override)
+
+    @patch("mcp_server.api_request")
+    @patch("mcp_server.get_auth_header")
+    def test_activate_profile_succeeds_when_enabled(self, mock_auth, mock_api):
+        self._write_config(CONFIG_SWITCHING_ENABLED)
+        
+        # Setup mock responses for whoami checks
+        mock_auth.side_effect = ["token author-pass", "token reviewer-pass"]
+        mock_api.side_effect = [{"login": "author-user"}, {"login": "reviewer-user"}]
+
+        with patch.dict(os.environ, self._env("author-profile"), clear=True):
+            # Check before state
+            self.assertEqual(gitea_config.selected_profile_name(), "author-profile")
+            
+            res = mcp_server.gitea_activate_profile(profile_name="reviewer-profile")
+            
+            self.assertTrue(res["success"])
+            self.assertEqual(res["before_profile"], "author-profile")
+            self.assertEqual(res["before_identity"], "author-user")
+            self.assertEqual(res["after_profile"], "reviewer-profile")
+            self.assertEqual(res["after_identity"], "reviewer-user")
+            
+            # Global variable override should be set
+            self.assertEqual(gitea_config._active_profile_override, "reviewer-profile")
+            self.assertEqual(gitea_config.selected_profile_name(), "reviewer-profile")
+
+    # -------------------------------------------------------------------------
+    # gitea_check_pr_eligibility enhanced error clarity
+    # -------------------------------------------------------------------------
+    @patch("mcp_server.api_request")
+    @patch("mcp_server.get_auth_header", return_value="token reviewer-pass")
+    def test_eligibility_failure_self_author(self, _auth, mock_api):
+        # PR is authored by "reviewer-user" and reviewer-user is trying to approve it.
+        mock_api.side_effect = [
+            {"login": "reviewer-user"}, # user whoami lookup
+            {"user": {"login": "reviewer-user"}, "state": "open", "head": {"sha": "abc123sha"}, "mergeable": True} # PR details
+        ]
+
+        with patch.dict(os.environ, self._env("reviewer-profile"), clear=True):
+            res = mcp_server.gitea_check_pr_eligibility(pr_number=42, action="approve")
+
+        self.assertFalse(res["eligible"])
+        self.assertEqual(res["active_identity"], "reviewer-user")
+        self.assertTrue(res["self_author"])
+        self.assertEqual(res["required_identity"], "Any Gitea user other than PR author 'reviewer-user'")
+        self.assertIn("Self-review/self-merge is forbidden", res["safe_next_step"])
+
+    @patch("mcp_server.api_request")
+    @patch("mcp_server.get_auth_header", return_value="token author-pass")
+    def test_eligibility_failure_missing_permissions(self, _auth, mock_api):
+        # PR is authored by "someone-else" and author-user (who lacks approve) is trying to approve it.
+        mock_api.side_effect = [
+            {"login": "author-user"}, # user whoami lookup
+            {"user": {"login": "someone-else"}, "state": "open", "head": {"sha": "abc123sha"}, "mergeable": True} # PR details
+        ]
+
+        self._write_config(CONFIG_SWITCHING_ENABLED) # Enable switching to verify fixable_by_profile_switch
+
+        with patch.dict(os.environ, self._env("author-profile"), clear=True):
+            res = mcp_server.gitea_check_pr_eligibility(pr_number=42, action="approve")
+
+        self.assertFalse(res["eligible"])
+        self.assertEqual(res["missing_permission"], "gitea.pr.approve")
+        self.assertTrue(res["fixable_by_profile_switch"])
+        self.assertFalse(res["requires_different_namespace"])
+        self.assertIn("Switch to a reviewer profile by calling gitea_activate_profile", res["safe_next_step"])
+
+    @patch("mcp_server.api_request")
+    @patch("mcp_server.get_auth_header", return_value="token author-pass")
+    def test_eligibility_failure_missing_permissions_switching_disabled(self, _auth, mock_api):
+        # PR is authored by "someone-else" and author-user (lacks approve) tries to approve it when switching is disabled.
+        mock_api.side_effect = [
+            {"login": "author-user"}, # user whoami lookup
+            {"user": {"login": "someone-else"}, "state": "open", "head": {"sha": "abc123sha"}, "mergeable": True} # PR details
+        ]
+
+        self._write_config(CONFIG_SWITCHING_DISABLED) # Disable switching
+
+        with patch.dict(os.environ, self._env("author-profile"), clear=True):
+            res = mcp_server.gitea_check_pr_eligibility(pr_number=42, action="approve")
+
+        self.assertFalse(res["eligible"])
+        self.assertEqual(res["missing_permission"], "gitea.pr.approve")
+        self.assertFalse(res["fixable_by_profile_switch"])
+        self.assertTrue(res["requires_different_namespace"])
+        self.assertIn("Switch to the reviewer MCP session", res["safe_next_step"])