symbol

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

No annotations are present, so the description carries the burden of behavioral disclosure. It adds 'exact', 'deterministic', and 'tiny' qualifiers, and hints at a prerequisite with 'prepared fast-query substrate', but it does not explain failure modes, return behavior when no match exists, or whether the substrate must be explicitly indexed.

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?

The description is two sentences, front-loaded with the action and followed by usage guidance. Every word contributes to understanding the tool's purpose or selection criteria, with no fluff.

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 simple lookup tool with full schema coverage and no output schema, the description covers purpose, usage, and key behavioral traits. The only minor gap is the unexplained 'prepared fast-query substrate', but the tool is simple enough that the description is nearly complete.

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?

The input schema provides full descriptions for both parameters (query and top_k), so schema coverage is 100%. The description adds no additional parameter-level detail beyond what the schema already states, so the baseline score of 3 is appropriate.

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 states the tool runs an exact symbol lookup against a prepared fast-query substrate, using a specific verb and resource. It also contrasts this with ranked related search, distinguishing it from the likely 'search' sibling.

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?

Explicitly tells the user when to use this tool: when the exact symbol name is known and deterministic exact matches are needed, instead of ranked related search. This provides clear selection criteria relative to alternative search behavior.

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