get_execution_path

Find the execution path between two symbols using Prize-Collecting Steiner Tree (PCST). Returns the minimum connected subgraph that links the source to the sink while respecting a token budget.

Input schema

{
  "type": "object",
  "required": ["source", "sink"],
  "properties": {
    "source": {
      "type": "string",
      "description": "Starting symbol or file path (e.g. 'src/routes/auth.ts#login')."
    },
    "sink": {
      "type": "string",
      "description": "Target symbol or file path (e.g. 'src/db/connection.ts#query')."
    },
    "token_budget": {
      "type": "integer",
      "default": 2000,
      "minimum": 200,
      "description": "Maximum tokens in the returned subgraph."
    },
    "repo": { "type": "string" }
  }
}

Output schema

{
  "type": "object",
  "properties": {
    "source": { "type": "string" },
    "sink":   { "type": "string" },
    "path": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "symbol":  { "type": "string" },
          "path":    { "type": "string" },
          "line":    { "type": "integer" },
          "edge":    { "type": "string", "description": "Edge kind connecting this node to the next." }
        }
      }
    },
    "tokens_used": { "type": "integer" },
    "found":       { "type": "boolean" }
  }
}

Example

Request:

{
  "source": "src/routes/auth.ts#login",
  "sink":   "src/auth/jwt.ts#sign",
  "token_budget": 1500
}

Response:

{
  "source": "src/routes/auth.ts#login",
  "sink":   "src/auth/jwt.ts#sign",
  "found":  true,
  "tokens_used": 847,
  "path": [
    { "symbol": "login",          "path": "src/routes/auth.ts",          "line": 24, "edge": "calls" },
    { "symbol": "AuthController.login", "path": "src/controllers/AuthController.ts", "line": 88, "edge": "calls" },
    { "symbol": "SessionService.create","path": "src/services/SessionService.ts",    "line": 41, "edge": "calls" },
    { "symbol": "sign",           "path": "src/auth/jwt.ts",             "line": 12, "edge": null }
  ]
}

When to use

• Security audit: trace the path from a public HTTP handler to a database write or crypto primitive.
• Debugging: find why a change in module A unexpectedly affects module B by tracing the execution path.
• Documentation: generate accurate call graphs for design docs.

Notes

• Returns "found": false if no path exists within the graph (the source and sink are not connected).
• PCST may return a path with intermediate "Steiner nodes" that are not direct call sites but bridge the connected components. These are marked with the edge field.