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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered; the description adds genuinely new behavior by disclosing the exact return payload including the `truncated` flag and the default-branch fallback when `ref` is omitted. It does not mention rate limits or error behavior, but the return-shape disclosure is valuable given no output schema exists.

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 compact sentences, front-loaded with what the tool is, then why it is dependable, then the return contract and the `ref` default. Every sentence carries information an agent needs and there is no filler.

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?

With five parameters, no output schema, and moderate schema coverage, the description correctly compensates by documenting the return object and the default-branch behavior. The remaining gap is that pagination/limit interplay (default 50, max 200) is left entirely to the schema and no error or empty-result behavior is described.

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 60%, so the schema documents `ref`, `limit`, and `query` while `owner`/`repo` are self-evident. The description's only parameter-relevant claim, 'Omit `ref` for the default branch,' restates what the schema already says, so it adds little meaning beyond the structured fields.

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?

States a specific verb and resource ('Literal / regex code search') plus the underlying mechanism ('git grep, basic regex') and scope ('across a repo at a ref'). The phrase 'works on every repo, indexed or not' implicitly separates it from indexed search siblings like semantic_search and repo_search, so an agent can route without opening the schema.

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?

Gives a clear selection condition: it is 'the dependable way to find code on this host — works on every repo, indexed or not,' which tells the agent to prefer it when indexing is unavailable or uncertain. It stops short of naming the alternative tools (semantic_search, find_symbol) or stating when-not to use it, so it falls short of a 5.

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