prospect_symbol

[SUPPORT] 2ce5bc76 — ROBUST symbol prospecting with a three-rung fallback chain: tries codebase__search_graph FIRST (fast, graph-indexed); when it returns zero results OR the caller flags a mismatch (stale_graph=true), automatically retries via Serena extractor__find_symbol / extractor__find_declaration (AST-accurate, never stale); falls back to a BM25 keyword grep over search_code_semantic as a last resort so the caller NEVER has to notice a miss and switch tools by hand. Each rung is labelled in the result ({rung: 'graph'|'serena'|'semantic', hits:[...], fallback_reason: str?}) so the caller knows which level succeeded. All three legs are best-effort: a missing tunnel, inactive slot, or missing root_dir degrades to the next rung, never a bare error with no diagnostic. d5e60791 — every rung's outcome is recorded under result.rungs.{graph,serena,semantic}: status ('not_attempted'|'skipped'|'attempted'|'succeeded'|'empty'|'error'), attempted_tool/selected_tool, and (on skip/error) a reason/error + error_kind ('dependency_error' vs 'runtime_error') — a missing dependency (e.g. an uninstalled local package) or any other runtime failure in a rung is NEVER silently collapsed into rung='none' with no trace; fallback_reason is always populated when every rung misses. 4b8f083f — when root_dir is a git checkout, the graph rung is ALSO auto-skipped (same as an explicit stale_graph=true, with fallback_reason 'graph_skipped_commit_drift_detected') whenever a cheap local git rev-list --count finds real commits since the last index_repository run for this project — no waiting for a _graph_staleness warning from the server, which only fires when a SIBLING process re-indexes, never when nobody re-indexes at all. Pass root_dir to get this protection. Use this instead of calling codebase__search_graph directly whenever you are prospecting for a symbol, function, or class location — it is structurally immune to the class of silent graph-index miss that previously returned wrong line numbers or empty results for real symbols. It is categorised as a Execute tool in the Meridian MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

prospect_symbol accepts 8 parameters: kind, limit, symbol, root_dir, project_id, session_id, stale_graph, project_name. Required: symbol. The full parameter table on this page comes from the server's own tool schema.

Register the Meridian MCP server in PolicyLayer and add a rule for prospect_symbol: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Meridian. Nothing to install.

prospect_symbol is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Yes. Add a rate_limit block to the prospect_symbol rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

Set action: deny in the PolicyLayer policy for prospect_symbol. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

prospect_symbol is provided by the Meridian MCP server (@meridianmcp/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.