fix(mcp): serve tools without a root index + make the front-load hook monorepo-aware (#964) (#966)

The MCP server gated tool availability on whether the server root had a
.codegraph/ index, so in a monorepo where only sub-projects are indexed the
agent saw zero tools — and couldn't reach an indexed sub-project even by
projectPath. A session started before `codegraph init` also never surfaced the
tools afterward. The Claude front-load hook had the mirror gap: it only walked
UP for an index, so it stayed silent at a monorepo root.

MCP server:
- Always expose the tool surface; when the root isn't indexed, send a
  per-project instructions variant (pass projectPath) instead of the
  "inactive" note. Safety comes from response SHAPE (success-shaped guidance,
  never isError), not from hiding tools.
- Reword the no-default-project guidance to be per-project, not per-session,
  and sharpen the projectPath schema description.

Front-load hook (UserPromptSubmit):
- Scan DOWN (bounded depth, workspace-root-gated) for indexed sub-projects and
  shape the injection by topology: front-load the one the prompt names, nudge
  about the rest, or list them when ambiguous.

Verified: full suite (1703 passed); a live two-package monorepo run confirms the
hook front-loads the correct sub-project with no cross-package leakage. The
front-load's net speed effect is the existing multi-file-vs-single-file
tradeoff, unchanged by this work.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -24,6 +24,8 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - CodeGraph now understands **Lombok**-generated methods in Java. `@Getter`, `@Setter`, `@Data`, `@Value`, and `@Builder` generate getters, setters, `builder()`, `equals`/`hashCode`/`toString`, and the `@Slf4j` `log` field at compile time, so those methods never appear in the source — and a `user.getName()`, `User.builder()`, or `log.info(...)` call used to resolve to nothing, silently breaking call-chain analysis (the agent would conclude the method didn't exist and reconstruct it by hand). Those members are now indexed from the annotations and fields, so they appear in `codegraph search` and `codegraph_explore`/`codegraph_node`, and callers trace through them like any hand-written method. They're marked as Lombok-generated so they read as generated, not hand-written; a method you write yourself is never overridden, static fields get no accessor, and a class without Lombok is unaffected. Thanks @git87663849. (#912)
 - `codegraph_explore` now follows **C and C++ function-pointer dispatch**. C does polymorphism with function pointers: a struct carries a function-pointer field, concrete functions are registered into it through a table (`static struct cmd commands[] = {{"add", cmd_add}, …}`), a designated initializer (`.handler = on_open`), or an assignment, and the code dispatches indirectly (`p->fn(argv)`). None of that was visible to analysis — the indirect call resolved to nothing, so `git`'s command runner looked like it called nothing and a vtable's implementations had no callers. CodeGraph now links the dispatch site to the registered handlers, keyed by the struct field, so "what runs when this dispatches?" traces from `p->fn(...)` into every function registered for that field. This covers the command-table idiom (git, redis) and the ops-struct/vtable idiom (curl's content-encoders, protocol handlers), including the case where a generic hook slot is reassigned from a registry (`h->func = found->fn`). It stays precise — distinct function-pointer fields don't cross-link, a plain data field is never treated as a dispatch, and a project without function-pointer dispatch is unaffected. (#932)
 - `codegraph_explore` now follows **GoFrame** route bindings in Go. GoFrame's standard router wires routes reflectively: the path and method live in a `g.Meta` struct tag on a request type (`` g.Meta `path:"/user/sign-in" method:"post"` ``), the controller method that serves it is matched by that request type, and the two are joined at runtime by `group.Bind(...)` — so there was no path string and no edge from a route to its handler, and "where is `/user/sign-in` handled?" or "where are the routes bound to controllers?" could only be answered by reading. CodeGraph now indexes each `g.Meta` route as a real route node and links it to the controller method whose signature takes that request type, so a route resolves to its handler structurally in one `codegraph_explore` call. The link is by request type, not method name — so it's correct even when the two differ (a `DeptSearchReq` served by a `List` method); it tells apart the many identical request types a large app defines one-per-module (`cash.ListReq` vs `order.ListReq`) by package, including cloned addon modules; and a route whose handler isn't present is left unlinked rather than guessed. (#747)
+- The MCP server now works in monorepos and multi-project setups. Before, if you started CodeGraph somewhere with no `.codegraph/` of its own — most often a monorepo root where you only indexed individual services — the server exposed **no tools at all**, so your agent couldn't query CodeGraph even for the sub-projects that *were* indexed. Now the tools are always available: point a query at any indexed project with the `projectPath` argument (its path, or anywhere inside it) and CodeGraph answers from that project's index — for as many projects as you like in one session. It also means a project you index *after* the server started is picked up without restarting, where before the tools stayed hidden because the server only checked for an index once at launch. A project that genuinely has no index still cleanly tells your agent to use its built-in tools there (and that you can run `codegraph init` to enable it), so single-project use is unchanged. Thanks @MaiLunJiye. (#964)
+- The Claude front-load hook now finds your indexed sub-projects in a monorepo. The optional `UserPromptSubmit` hook that injects CodeGraph context for structural questions previously only looked for an index at or above your working directory — so if you opened the monorepo root but indexed individual packages (`packages/api`, `services/auth`), it found nothing and stayed silent exactly where it was most useful. It now also looks *into* sub-projects: a single indexed sub-project gets its context front-loaded automatically, and with several the hook front-loads the one your question names (and lists the rest so the agent can target them by `projectPath`). Single-project repos are unaffected, and the scan is bounded and skipped entirely outside a recognizable workspace root. (#964)
 
 - `codegraph_explore` now surfaces the right code in large multi-layer projects. When you ask a backend-flow question in a repo that pairs an API server with a big frontend that mirrors the same domain words — say an `app/` admin UI sitting over an `api/` server — the server-side file that genuinely matches several of your query's terms is no longer pushed out of the results by the larger, more interconnected frontend layer. A file corroborated by two or more distinct query terms is now kept in the answer even when a denser unrelated layer would otherwise crowd it out, so "how does X read items / handle the request" returns the service or handler that does the work instead of a wall of frontend views. Single-layer projects are unaffected; set `CODEGRAPH_RANK_NO_MULTITERM=1` to revert to the previous ranking.
 - Impact and blast-radius analysis for TypeScript, JavaScript, Go, Python, Rust, Ruby, C, Java, C#, PHP, Scala, Kotlin, Swift, Dart, and Pascal/Delphi now understands the readers of a constant. When you change a file-scope, package-level, module-level, or class-level constant — a config object, a lookup table, a shared constant — the other symbols in that file that read it now show up as affected, where before they were invisible (impact only followed calls, imports, and inheritance, so a constant's consumers looked like "nothing depends on this"). This makes `codegraph impact`, and the impact trail in `codegraph_explore`/`codegraph_node`, catch the "change this table, break its readers" class of change. It's on by default and adds no nodes to your graph; bundled/minified files and ambiguously-shadowed names are skipped to keep results precise. Set `CODEGRAPH_VALUE_REFS=0` to turn it off.