chemenu/raw/notes/Conversation Transcript - MCP Read Server Implementation Session 2026-09-02.md

Conversation Transcript - MCP Read Server Implementation Session

Source: Claude Code session (claude-opus-5), chemenu workspace Collected: 2026-09-02 Participant: Torben Fidelity: faithful summary transcript, not a verbatim log. Torben's instructions are quoted verbatim; the assistant's design reasoning, code, and file contents are condensed to what a later reader needs to find the artifact - the artifacts themselves are the code, not this transcript. Command outputs shown (test counts, timings, the Mass-Update Gate's printed file list, gate refusal messages) are real, copied from the session. No credentials appeared. No subagents were used - all work in this transcript is first-hand. One of two transcripts cut from this session; the other covers fixing kb/entities/tools/qmd.md, a documentation defect noted but not fixed during this one.

Covers implementing the four-issue sequence held by #36 (the master issue for "path to the MCP read server"): #34 (arm the Publish-Remote Gate), #33 (harden the read path), #31 (root resolution + library boundary), #19 (the MCP server itself), plus the human-facing INSTALL-MCP.md and filing #37 (the container-image follow-up) that #19's closure surfaced as still missing. Four version bumps in sequence: 2.2.3, 2.2.4, 2.3.0, 2.4.0, then 2.4.1 for the documentation follow-up. All five touched issues (#34, #33, #31, #19, #36) got closing comments; #36 was left open pending #37.

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Turn 1 - /stack-dev implementiere #36

The stack-dev skill loaded, switching the session into tool-development rules (ordinary software-engineering judgment on tools/, types/, instructions/ - no source-binding, no raw/ citation needed for code).

Read issue #36 (the master issue) via gitea-mcp. It holds no implementation itself - a sequence table (#34 → #33 → #31 → #19), a table of platform/auth/transport decisions already made and closed to debate, a measured baseline (593 ms per wikitool search, broken down: 262 ms module import, 274 ms corpus parse, 7 ms ripgrep), ten verified findings backing the design, and an explicit "not in scope" list (Go, deployment details, a write path, #15's research capability). Read #34, #33, #31, #19 in full including comments to get the acceptance criteria and the reasoning behind each.

Worked the sequence in order, starting a session-scoped WIKITOOL_SESSION_ID.

#34 - Publish-Remote Gate. .wikitool-remotes.json did not exist in this checkout; absence means unrestricted per git_publish.read_allowed_push_urls(). Created it with origin's exact push URL as the sole allowed target. Counter-checked by adding a second git remote to a made-up URL and running publish --remote gatecheck: refused with exit 42, working tree untouched, before any fetch. Remote removed afterward.

doctor's check_publish_remotes() reported only whether the file existed, not whether the gate was actually armed. Rewrote its three outcome messages to lead with Gate armed: / Gate not armed: explicitly - the single-remote-no-file case stays OK (nothing to protect, and a FAIL would make the file mandatory through the back door) but now says outright that every push target passes. The check had no tests; added three, one per state.

Bumped --patch → 2.2.3.

#33 - Harden the read path. Six findings, each addressed with a regression:

1. ReDoS. search/ripgrep.py:_contains passed query.regex to re.search. Deleted the branch entirely rather than bounding it - rg already applies the pattern with a linear engine before this function runs, so nothing is lost except the extra title/summary ranking boost for a non-literal pattern (and summary/H1 lines are themselves counted by rg). Regression test asserts both the timing (< 0.5s against (\w+\s?)+$) and the return value, because a bound alone would pass with a merely-faster engine.
2. No subprocess timeout. Added RIPGREP_TIMEOUT_SECONDS = 30.0; TimeoutExpired translates to the existing RipgrepFailed path.
3. YAML aliases. Frontmatter has no legitimate use for anchors/aliases, so they are refused outright rather than budgeted, checked on the streaming event parse (yaml.parse) so the check itself never triggers the expansion it is checking for - * is a necessary character in any alias node, so its absence proves absence with zero parse cost. Constructed a reproduction: 267 bytes of nested aliases compose into 672,603 nodes on traversal at constant (0.2 ms) parse time, growth 9^n with nesting depth. Added a 64 KiB frontmatter size limit and a RecursionError catch (PyYAML composes recursively; deep nesting is not a YAMLError).
4. CSafeLoader unused. Switched to it with a SafeLoader fallback. Measured over this corpus (176 pages, best of 5): 265 ms → 54 ms.
5. Silent frontmatter loss. Decided: the read path now reports rather than swallows. Unparseable YAML still degrades to {} for bulk operations, but the reason travels with it (Page.frontmatter_error, set by a single parser shared between read_page() and frontmatter_error() - previously two separate safe_load call sites that could describe the same broken file differently). search --json now always carries an unreadable list of {path, reason}; the table form writes the same lines to stderr. Added read_page_strict() for the future ingest-quarantine path (#32), which must stop on unparseable input rather than empty it.
6. Corpus reparse per call. New chemenu/corpus_cache.py: a CorpusCache object a caller holds (not a module-global switch). The CLI holds none and is unaffected. Correctness property, not just speed: a dirty working tree is never cached - if git cannot answer whether the tree is clean, it is treated as dirty. wikitool search end-to-end (best of 5): 593 ms → 347 ms.

Bumped --patch → 2.2.4.

#31 - Root resolution + library boundary. config.ROOT and everything derived from it were Python module constants, bound at import time from Path(__file__).resolve().parents[2] - so monkeypatch.setattr(config, "ROOT", tmp_path) repointed ROOT but left KB_DIR/RAW_DIR aimed at the real checkout, the exact failure class raw_dir's own fixture docstring already warned about one layer up.

Rewrote config.py: resolve_root() by precedence (explicit argument → $CHEMENU_ROOT → walk-up, the walk-up staying default so tools/wikitool is unaffected), and every derived path resolved on attribute access via module __getattr__ (PEP 562) rather than stored - so an assignment onto ROOT (test or otherwise) is honored by every path under it, live. This surfaced a subtler bug while fixing the first one: monkeypatch's own undo mechanism reads the old value (which resolves it) and writes it back as a real attribute on teardown, recreating the stale binding the rewrite was meant to eliminate. Added config.reset(), called by the autouse hermetic-environment fixture on both setup and teardown.

Split the CLI-coupled command modules into a pure core + thin adapter, three times over: search/service.py, lint_core.py, types_core.py - none of them import typer or rich. commands/search.py, commands/lint.py, commands/types_cmd.py became the terminal adapters, re-exporting the same names so no existing import breaks.

New chemenu/errors.py: ChemenuError → ValidationError (also inherits ValueError, since PredicateError already was one and callers catch it that way) / BackendError. PredicateError, FrontmatterError, UnknownBackend, RipgrepMissing, RipgrepFailed moved under this hierarchy.

New chemenu/api.py: Corpus class, the in-process entry point - takes a root, returns exactly the CLI's --json shapes, raises instead of exiting, stamps every response with commit/ as_of. Wrote the acceptance test by monkeypatching Path.read_text/Path.rglob to fail on any access under the real checkout root while a foreign root is set - this test could not have passed before the lazy-resolution rewrite.

Two more accidental dependencies surfaced and were fixed: TypeResolver.repo_root was also import-bound (fixed the same way, with config.rooted() as a process-wide context manager for callers that reach config directly rather than taking a root argument - and use_shipped_type_specs() added to the test fixtures that had been relying on it silently); and search/registry.resolve() did not pass kb_dir/root through to the backend, so a caller pointing run_search at a foreign corpus could still have RipgrepBackend read config.KB_DIR underneath it.

Bumped --minor → 2.3.0 (new capability, backward-compatible).

#19 - MCP read server. New package tools/chemenu/mcp/ (server.py, __main__.py). Installed the mcp SDK (mcp>=2.0, discovered mid-session that this pulled in the v2 API - FastMCP renamed to MCPServer, imported from mcp.server.mcpserver). Five tools over chemenu.api.Corpus: search, types, describe_type, lint, status (status is server-composed, not a wrapper - there is no wikitool status command to wrap). No write tool, structurally: neither the server module nor chemenu.api imports anything under chemenu.commands.

Both transports built and smoke-tested end-to-end against the real 176-page corpus: stdio via a hand-written MCP client script, and streamable-http (host/port bound explicitly - the default binds loopback, wrong for a container behind a proxy) via a subprocess + HTTP client round-trip. sse deliberately not offered (superseded transport).

ChemenuError translated to the SDK's ToolError at the tool-call boundary (a deliberate refusal whose message reaches the caller) rather than left to become an UnexpectedToolError (a crash whose message stays server-side).

Found and fixed a stamping bug while writing the golden test: _stamp() was asking the cache for the current revision after the load had already happened, so a caller with a perfectly clean tree could see "commit": null if the cache's cached revision lagged. Fixed by threading the revision the load actually returned through to the stamp.

Wrote tools/chemenu/tests/test_mcp_server.py: the golden test runs wikitool ... --json as a subprocess against the same fixture tree (via $CHEMENU_ROOT) and asserts the server's structured output matches field-for-field; a before/after test captures file size+contents, git rev-parse HEAD, and git status --porcelain around all five tool calls to prove nothing writes; a structural test imports the server module in a fresh interpreter and checks sys.modules for absence of chemenu.commands.*.

Added check_trace_destination(): the server refuses to start if WIKI_TRACE is on and would write into the served checkout's reports/telemetry/ - the directory the sync's git reset --hard is entitled to wipe. WIKI_TRACE=0 or WIKI_TRACE_DIR outside the corpus both satisfy it.

New instructions/mcp-read-server.md (agent-facing operating procedure), tools/requirements-mcp.txt (the SDK's dependency, kept out of requirements.txt so a CLI-only instance need not install pydantic/starlette/uvicorn/cryptography), a CI step to install it (so the golden test cannot silently be skipped), and doc updates (tools/CONTRACT.md, tools/README.md, README.md).

Bumped --minor → 2.4.0.

Ran docs verify, instructions verify, and the full suite (799 passed) plus an empty-machine run (env -i ... pytest) with the same result, before presenting the changeset.

tools/wikitool publish hit the Mass-Update Gate: 37 files, +3,037/-625 lines, exit 42. Reproduced the full file-by-area breakdown verbatim in the reply (as the gate's message requires - the output does not reach the user's screen on its own) and stopped without running further commands, per the gate's instruction and AGENTS.md invariant 6.

Turn 2 - "Freigegeben. Erstelle eine install-MCP.md für Menschen. Für traefik middleware verweise auf https://gitea.nehmer.net/torben/gitea-mcp-forward-auth ... Wir brauchen ein issue, der uns dicker Container für ein deployment erzeugt. Fasse dort schon mal zusammen, was du bisher weißt... Die ci scripte in https://gitea.nehmer.net/torben/gitea-mcp dürfte ein guter startpunkt sein."

Published with the token from the gate's own printed line (--confirm 46442f4419c1) - commit 576df2c.

Fetched both referenced repos via gitea-mcp (get_repository_tree, get_file_contents) to ground the two follow-up documents in what actually exists rather than in assumption:

• gitea-mcp-forward-auth: a small Go Traefik ForwardAuth service - Bearer-token-vs-SHA-256-hash checking, AUTH_PROXY_TOKEN_HASHES_DIR/AUTH_PROXY_TOKEN_HASHES config, /healthz always open, demo token hashes checked into the repo, a registry-image test script with ephemeral Docker/Podman login.
• gitea-mcp: its Dockerfile (multi-stage, CGO_ENABLED=0, distroless non-root, OCI labels) is a usable pattern, but its release workflow pushes to DockerHub (DOCKER_ORG: gitea) - it is a fork of the upstream project, so it is not a usable registry-push template for this repo. Noted explicitly rather than silently copied.

Wrote install-MCP.md (later renamed, see Turn 3): six numbered steps (install dependency, run stdio, wire a client, run streamable-http, put authentication in front, keep the corpus current via polling), a runnable stdio verification script (executed for real before being written into the doc, output: Tools: [...], Seiten: 176 | Commit: <sha>), and a troubleshooting section keyed to the server's actual error messages. Linked it from INSTALL.md and README.md, and added CHEMENU_ROOT/WIKI_TRACE/WIKI_TRACE_DIR to INSTALL.md's configuration table (both had been in effect since earlier work but undocumented there). Added the file to dist_cmd.py's ROOT_FILES allowlist and verified with a real dist export that it ships.

Filed issue #37 ("Container-Image für den MCP-Leseserver"): summarized what is already fixed (startup command, required env vars, the ripgrep-in-the-image trap a naive pip install Dockerfile would miss, where auth/rate-limiting belong) and the concrete templates found above, then nine explicit open decisions (corpus baked into the image vs. mounted as a volume and synced by a sidecar; who runs the sync; base image, since Go-style distroless does not carry a Python interpreter or rg; how the version reaches the image; whether to build arm64; a healthcheck endpoint does not exist yet - the one item that implies new code in this repo; registry path; OCI labels; whether a smoke test against the built image is added). Labeled prio/2 size/M.

Closed #34, #33, #31, #19 with detailed comments each restating what was implemented against the issue's own acceptance criteria, including the two accidental-dependency findings from #31 and the corrected alias-bomb numbers. Commented on #36 with a summary table across all four versions, noted its closing criterion (a consumer provably reaching the server through the Traefik middleware) is not yet met - that needs #37's deployment - and proposed leaving #36 open until then; also carried forward its two remaining loose ends (the wrong qmd.md language claim, and the still-missing place for architecture decisions).

Turn 3 - "Freigegeben. Nenne die Datei INSTALL-MCP.md all Caps sonst fahre mit dem Auftrag fort" (interrupting a dist export verification call)

Renamed install-MCP.md → INSTALL-MCP.md, fixed every reference (INSTALL.md, README.md, tools/chemenu/commands/dist_cmd.py). Re-ran the full suite (799 passed) and docs verify, bumped --patch → 2.4.1, wrote the changelog entry, published (commit 83018fc). Saved a feedback memory (root-docs-are-all-caps.md): root-level human docs in this repo are named in ALL CAPS, and a new one has to be added to dist_cmd.ROOT_FILES or it silently does not ship.

Outcome

• Version: 2.2.2 -> 2.2.3 -> 2.2.4 -> 2.3.0 -> 2.4.0 -> 2.4.1
• Commits: 576df2c (2.4.0, the 37-file changeset cleared through the Mass-Update Gate), 83018fc (2.4.1, INSTALL-MCP.md and its wiring)
• Tests: 776 -> 786 -> 799 passed, green throughout, including on an env -i empty machine
• Measured: corpus parse 265ms -> 54ms; wikitool search end-to-end 593ms -> 347ms
• Issues: #34, #33, #31, #19 closed with detailed comments; #36 commented, left open pending #37; #37 opened (prio/2 size/M)
• CI: .gitea/workflows/ci.yml updated to install tools/requirements-mcp.txt, otherwise unchanged; not separately re-run in this session (publish triggers it)
• Not done in this session, carried forward: #37 itself (container image); #23 (env var registration enforcement - CHEMENU_ROOT was added to _WIKITOOL_ENV by hand); the qmd.md language-claim fix (separate transcript); an ADR-style home for architecture decisions