ast_search

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the burden. It discloses key behavior: syntax-aware AST matching via ast-grep, the use of metavariables, and the return format. It could add details about error handling or read-only guarantees, but for a search tool the disclosed behavior and output are useful and unambiguous.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, each earning its place: first states the core capability, second gives usage guidance, third describes the return value. No repetition of schema details; front-loaded with the most important information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a search tool with 4 params and no output schema, the description is largely complete: it covers what the tool does, when to use it, the mechanism, and the return format. Minor gaps include not addressing invalid patterns or language support nuances, but these are not critical for a search-oriented task.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3. The description adds meaningful semantics for the pattern parameter by explaining metavariables ($X, $$$ARGS) and providing an example, complementing the schema's terse 'ast-grep pattern' description. Other parameters are adequately covered by the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's function: 'Structural code search via ast-grep' with specific mechanism ('match a syntax-aware pattern'), resource (code), and output ('Returns file/line/matched text'). It also distinguishes itself from text grep by emphasizing syntax-aware matching with metavariables.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states when to use it: "Use for 'every call site shaped like this' questions a text grep gets wrong," providing clear context. It contrasts with text-based grep, which implies an alternative, though it does not name a specific sibling tool or explicit when-not-to-use cases.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.