feat(xrepo): cross-repo intelligence — multi-repo query via --additional-paths (closes #15)

[Wolfvin]

Closes #15

Summary

Implements the Minimum Viable Version from issue #15:

Just support multiple repo_path entries — resolve imports against the combined symbol table from all indexed repos.

Agents can now query across pre-indexed repos:

codelens query shared_helper /projects/services/api --additional-paths /projects/lib/shared

Returns the symbol from lib/shared, with the caller from services/api annotated cross_repo: true — so an agent can trace a call that crosses the repo boundary without manually chaining trace → search → query.

What was added

File	Purpose
scripts/crossrepo_engine.py	load_merged_registry() — loads backend registries from primary + additional repos, tags each node with repo, re-runs resolve_edges() on the combined node set so cross-repo calls resolve automatically. Cross-repo edges flagged with cross_repo=True + target_repo + source_repo. query_cross_repo() — multi-repo symbol query with callers/callees annotated.
scripts/commands/query.py	Added --additional-paths flag. When provided, delegates to crossrepo_engine.query_cross_repo(). When absent, behavior is unchanged (zero-risk backward compat).
scripts/mcp_server.py	Added additional_paths parameter to the codelens_query MCP tool schema so agents can pass comma-separated repo paths.
tests/test_crossrepo_engine.py	28 tests: path parsing, registry merging, cross-repo edge resolution, multi-repo query, fuzzy match across repos, graceful degradation, CLI arg integration.
README.md, SKILL.md, SKILL-QUICK.md, pyproject.toml, skill.json, scripts/graph_model.py	Auto-synced by sync_command_count.py --apply (command count 68→69 from other workers' merged PRs; this PR itself adds 0 new commands).

How it works

The key insight: edge_resolver.resolve_edges() already matches to_fn (function name) against the full node list to resolve cross-file calls. By feeding it nodes from multiple repos, cross-repo calls resolve automatically — the resolver doesn't care which repo a node came from.

Repo A (services/api)          Repo B (lib/shared)
┌─────────────────────┐       ┌─────────────────────┐
│ caller_fn           │       │ shared_helper       │
│   calls shared_helper──────▶│                     │
│   calls local_fn    │       └─────────────────────┘
└─────────────────────┘
         │
         ▼  After merge + re-resolve:
         edge: from=caller_fn, to=shared_helper,
               cross_repo=True, source_repo=A, target_repo=B

Non-breaking by design

• scan / init / load_backend_registry untouched — each repo is scanned independently as before. No config schema changes required.
• resolve_edges reused as-is — it already does the heavy lifting; we just feed it a bigger node list.
• query without --additional-paths — identical behavior, same code path, zero risk.
• No new CLI commands — only a new flag on the existing query command.

Test results

PYTHONUTF8=1 PYTHONPATH=scripts python -m pytest tests/ --ignore=tests/test_integration.py

1398 passed, 80 skipped, 1 failed (28 new tests included in the 1398).

The 1 failure (test_codelensignore::TestBackwardCompat::test_actual_target_dir_is_ignored) is pre-existing and unrelated — it fails identically on clean origin/main.

Scope alignment with multi-worker analysis

Per the aggregation comment on #15, three worker reports proposed different scopes:

• CodeGraph feat(types): hybrid type resolution — closes #13 #29 = multi-repo querying within MCP (read-only across pre-indexed projects) — this PR implements this scope
• Repomix R5 = remote repo fetch-and-scan (--remote) — future work
• Serena S14 = intra-monorepo cross-package via LSP workspace folders — narrower problem

This PR implements the CodeGraph #29 scope: read-only multi-repo querying across pre-indexed projects. The other two scopes can be addressed in sibling issues.

Limitations (documented, not bugs)

• Read-only. No cross-repo scan or indexing — each repo must be scanned independently first.
• Backend-only. Frontend registry merging is not implemented (frontend symbols don't have call edges in the same way). Can be added if needed.
• trace command not yet updated. Only query gained --additional-paths in this MVP. trace --additional-paths can follow in a subsequent PR.
• No CROSS_CALLS / CROSS_IMPORTS edge types. The issue body suggests distinct edge types, but the MVP uses a cross_repo: true flag on existing CALLS edges instead — simpler, non-breaking, and carries the same information.

[chatgpt-codex-connector]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud