agents: Sourcebot-MCP für Repos ohne lokalen Checkout dokumentieren

Deterministische Tools (grep/read_file/get_diff/find_symbol_*) für
Recherche in nicht geklonten Seibert-Repos; ask_codebase nur auf
explizite Anweisung (verschachtelter Server-Agent, Minuten pro Call).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Q6JHuFiJ86AyyMqyTaTcHi

agents/AGENTS.md

@@ -94,6 +94,17 @@ Treat vague input and question-back responses critically, not as instructions.
 
 ## Tooling
 
+- **Sourcebot MCP for org repos without a local checkout.** The
+  `mcp__sourcebot__*` tools (instance sourcebot.it.seibert.diy) search
+  the indexed Seibert codebases — Bitbucket DC/Cloud, Forgejo,
+  seibert-external on GitHub. Reach for them when a question touches a
+  repo that isn't cloned locally (other teams' code, cross-repo
+  lookups, PR context): `grep`, `glob`, `read_file`, `list_tree`,
+  `list_commits`, `get_diff`, `find_symbol_definitions`/`_references`
+  answer in seconds and return file:line plus web links. A local
+  checkout stays first choice when it exists. Never call
+  `ask_codebase` on your own — it spawns a nested server-side agent
+  (minutes per call, shared vLLM); use it only when explicitly asked.
 - **`ccc` for semantic code search.** Repos containing a
   `.cocoindex_code/` directory are indexed by
   [`ccc`](https://github.com/cocoindex-io/cocoindex-code). Reach for