feat: cross-repo impact analysis (#794) — @repo MCP routing + group resources

.gitignore

@@ -103,3 +103,6 @@ gitnexus/vendor/**/node_modules/
 
 local_docs/
 
+# Local agent scratch / review prompts (never commit)
+.tmp/
+.agents/

AGENTS.md

@@ -47,6 +47,7 @@ Commands and gotchas live under **Repo reference** below and in **[CONTRIBUTING.
 
 | Date | Version | Change |
 |------|---------|--------|
+| 2026-04-19 | 1.5.0 | Cross-repo impact (#794): `impact`/`query`/`context` accept `repo: "@<group>"` + `service`. Removed `group_query`/`group_contracts`/`group_status` MCP tools; added `gitnexus://group/{name}/contracts` and `gitnexus://group/{name}/status` resources. |
 | 2026-04-16 | 1.4.0 | Fixed: web UI description, pre-commit behavior, MCP tools (7->16), added gitnexus-shared, removed stale vite-plugin-wasm gotcha. |
 | 2026-04-13 | 1.3.0 | Updated GitNexus index stats after DAG refactor. |
 | 2026-03-24 | 1.2.0 | Fixed gitnexus:start block duplication. |
@@ -107,10 +108,12 @@ Indexed as **GitNexus** (4325 symbols, 10556 relationships, 300 execution flows)
 | `tool_map` | MCP/RPC tool definitions | `gitnexus_tool_map({})` |
 | `shape_check` | Response shape vs consumer access | `gitnexus_shape_check({route: "/api/users"})` |
 | `group_list` | List repo groups | `gitnexus_group_list({})` |
-| `group_query` | Cross-repo search in a group | `gitnexus_group_query({name: "myGroup", query: "auth"})` |
 | `group_sync` | Rebuild group Contract Registry | `gitnexus_group_sync({name: "myGroup"})` |
-| `group_contracts` | Inspect group contracts | `gitnexus_group_contracts({name: "myGroup"})` |
-| `group_status` | Group staleness report | `gitnexus_group_status({name: "myGroup"})` |
+| `query` (group mode) | Cross-repo search in a group (RRF-merged) | `gitnexus_query({repo: "@myGroup", query: "auth"})` |
+| `context` (group mode) | 360° view across all member repos | `gitnexus_context({repo: "@myGroup", name: "validateUser"})` |
+| `impact` (group mode) | Cross-repo blast radius via Contract Bridge | `gitnexus_impact({repo: "@myGroup", target: "X", direction: "upstream"})` |
+
+> Group mode: pass `repo: "@<groupName>"` to fan out across all member repos, or `repo: "@<groupName>/<memberPath>"` to target a single member (path keys from `group.yaml`). Optional `service: "<monorepo/path>"` filters by service root. Group-level state (contracts, staleness) lives in the resources table below — there are **no** `group_query` / `group_context` / `group_impact` / `group_contracts` / `group_status` MCP tools.
 
 ## Impact Risk Levels
 
@@ -128,6 +131,8 @@ Indexed as **GitNexus** (4325 symbols, 10556 relationships, 300 execution flows)
 | `gitnexus://repo/GitNexus/clusters` | All functional areas |
 | `gitnexus://repo/GitNexus/processes` | All execution flows |
 | `gitnexus://repo/GitNexus/process/{name}` | Step-by-step execution trace |
+| `gitnexus://group/{name}/contracts` | Group Contract Registry (provider/consumer rows + cross-links) |
+| `gitnexus://group/{name}/status` | Per-member index + Contract Registry staleness report |
 
 ## Self-Check Before Finishing
 

ARCHITECTURE.md

@@ -42,10 +42,14 @@ Monorepo: **CLI/MCP** (`gitnexus/`) + **browser UI** (`gitnexus-web/`).
 | `tool_map` | MCP/RPC tool definitions and handlers |
 | `shape_check` | Response shape vs consumer property access mismatches |
 | `group_list` | List repo groups or details for one group |
-| `group_query` | Cross-repo search in a group (reciprocal rank fusion) |
-| `group_sync` | Rebuild group Contract Registry (`contracts.json`) |
-| `group_contracts` | Inspect group contracts and cross-links |
-| `group_status` | Index and Contract Registry staleness per repo in a group |
+| `group_sync` | Rebuild group Contract Registry (`contracts.json`) and bridge graph |
+
+`query`, `context`, and `impact` are group-aware: pass `repo: "@<groupName>"` (or `"@<groupName>/<memberPath>"` to scope to one member) plus optional `service: "<monorepo/path>"`. Group-mode `query` merges per-repo results via Reciprocal Rank Fusion; group-mode `impact` runs the local walk in the chosen member and fans out across boundaries via the Contract Bridge (`gitnexus/src/core/group/cross-impact.ts`). The previously-planned `group_query`, `group_context`, `group_impact`, `group_contracts`, `group_status` MCP tools are intentionally not introduced — group-level state is exposed via resources instead:
+
+| Resource URI | Purpose |
+|--------------|---------|
+| `gitnexus://group/{name}/contracts` | Contract Registry (provider/consumer rows + cross-links) |
+| `gitnexus://group/{name}/status` | Per-member index + Contract Registry staleness |
 
 ## Where to change what
 
@@ -55,6 +59,7 @@ Monorepo: **CLI/MCP** (`gitnexus/`) + **browser UI** (`gitnexus-web/`).
 | Parsing/graph construction | `src/core/ingestion/pipeline-phases/` + `pipeline.ts` |
 | Graph schema/DB | `src/core/lbug/` (`schema.ts`, `lbug-adapter.ts`) |
 | MCP tools/resources | `src/mcp/server.ts`, `tools.ts`, `resources.ts` |
+| Cross-repo groups (sync, contracts, `@<group>` routing) | `src/core/group/` (`service.ts`, `cross-impact.ts`, `sync.ts`, `bridge-db.ts`) |
 | Search ranking | `src/core/search/` (BM25, hybrid fusion) |
 | Embeddings | `src/core/embeddings/` + `src/core/run-analyze.ts` |
 | Wiki generation | `src/core/wiki/` |

gitnexus/CHANGELOG.md

@@ -2,6 +2,12 @@
 
 All notable changes to GitNexus will be documented in this file.
 
+## [Unreleased]
+
+### Performance
+
+- **`analyze` ~33% faster** — moved FTS index creation from the analyze pipeline to first-use lazy initialisation. The 5 `CREATE_FTS_INDEX` calls cost ~440 ms each in LadybugDB regardless of table size (≈2 s fixed overhead) and dominated runtime on small repos and slow CI runners. The cost now amortises across the first `query`/`context` call in a session via a new `ensureFTSIndex` helper. Mini-repo `analyze` measured locally on Windows: 6.4 s → 4.0 s warm; on CI Windows runners (≈3× slower) restores comfortable headroom against the 30 s e2e test budget.
+
 ## [1.6.2] - 2026-04-18
 
 ### Added

gitnexus/src/cli/ai-context.ts

@@ -121,7 +121,7 @@ ${
   groupNames && groupNames.length > 0
     ? `## Cross-Repo Groups
 
-This repository is listed under GitNexus **group(s): ${groupNames.join(', ')}** (see \`~/.gitnexus/groups/\`). For blast radius across repository boundaries, use MCP tools \`group_impact\`, \`group_sync\`, \`group_query\`, \`group_contracts\`, \`group_status\`, and \`group_list\`. From the terminal: \`npx gitnexus group list\`, \`npx gitnexus group sync <name>\`, \`npx gitnexus group impact <name> --target <symbol> --repo <group-path>\`.
+This repository is listed under GitNexus **group(s): ${groupNames.join(', ')}** (see \`~/.gitnexus/groups/\`). For cross-repo analysis, use MCP tools \`impact\`, \`query\`, and \`context\` with \`repo\` set to \`@<groupName>\` or \`@<groupName>/<memberPath>\` (paths match keys in that group’s \`group.yaml\`). Use \`group_list\` / \`group_sync\` for membership and sync. From the terminal: \`npx gitnexus group list\`, \`npx gitnexus group sync <name>\`, \`npx gitnexus group impact <name> --target <symbol> --repo <group-path>\`.
 
 `
     : ''

gitnexus/src/cli/group.ts

@@ -184,6 +184,83 @@ export function registerGroupCommands(program: Command): void {
       }
     });
 
+  group
+    .command('impact <name>')
+    .description('Cross-repo impact for a symbol in one member repo of a group')
+    .requiredOption('--target <symbol>', 'Symbol or file name to analyze')
+    .requiredOption(
+      '--repo <groupPath>',
+      'Member path from group.yaml (e.g. app/backend), not the indexed repo name',
+    )
+    .option('--direction <dir>', 'upstream or downstream', 'upstream')
+    .option('--service <path>', 'Optional monorepo service directory prefix (path filter)')
+    .option(
+      '--subgroup <path>',
+      'Optional prefix limiting which group repos participate in cross fan-out',
+    )
+    .option('--max-depth <n>', 'Max graph traversal depth')
+    .option('--cross-depth <n>', 'Cross-repository hop depth')
+    .option('--min-confidence <n>', 'Minimum relation confidence (0–1)')
+    .option('--include-tests', 'Include test files in traversal', false)
+    .option('--timeout-ms <n>', 'Phase-1 local impact wall time in milliseconds')
+    .option('--json', 'JSON output')
+    .action(async (name: string, opts: Record<string, string | boolean | undefined>) => {
+      const { LocalBackend } = await import('../mcp/local/local-backend.js');
+
+      const backend = new LocalBackend();
+      try {
+        await backend.init();
+
+        const payload: Record<string, unknown> = {
+          name,
+          repo: opts.repo,
+          target: opts.target,
+          direction: (opts.direction as string) || 'upstream',
+        };
+        if (opts.service) payload.service = opts.service;
+        if (opts.subgroup) payload.subgroup = opts.subgroup;
+        if (opts.maxDepth !== undefined && opts.maxDepth !== '') {
+          const n = parseInt(String(opts.maxDepth), 10);
+          if (!Number.isNaN(n)) payload.maxDepth = n;
+        }
+        if (opts.crossDepth !== undefined && opts.crossDepth !== '') {
+          const n = parseInt(String(opts.crossDepth), 10);
+          if (!Number.isNaN(n)) payload.crossDepth = n;
+        }
+        if (opts.minConfidence !== undefined && opts.minConfidence !== '') {
+          const n = parseFloat(String(opts.minConfidence));
+          if (!Number.isNaN(n)) payload.minConfidence = n;
+        }
+        if (opts.timeoutMs !== undefined && opts.timeoutMs !== '') {
+          const n = parseInt(String(opts.timeoutMs), 10);
+          if (!Number.isNaN(n)) payload.timeoutMs = n;
+        }
+        if (opts.includeTests) payload.includeTests = true;
+
+        const raw = await backend.getGroupService().groupImpact(payload);
+        if (raw && typeof raw === 'object' && 'error' in raw) {
+          console.error(String((raw as { error: string }).error));
+          process.exitCode = 1;
+          return;
+        }
+
+        if (opts.json) {
+          console.log(JSON.stringify(raw, null, 2));
+        } else {
+          const summary = (raw as { summary?: Record<string, number> })?.summary;
+          const risk = (raw as { risk?: string })?.risk;
+          console.log(`Group impact for "${name}" (${String(opts.repo)}): risk=${risk ?? '?'}`);
+          if (summary) {
+            console.log(
+              `  direct=${summary.direct ?? 0} processes=${summary.processes_affected ?? 0} cross=${summary.cross_repo_hits ?? 0}`,
+            );
+          }
+        }
+      } finally {
+        await backend.dispose().catch(() => {});
+      }
+    });
+
   group
     .command('query <name> <query>')
     .description('Search execution flows across all repos in a group')