definition

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

With no annotations, the description carries the full burden. It discloses that a bare name resolves only when unique in the project, which is a useful resolution rule, but it never states that this is a read-only lookup, nor what happens on ambiguity or unknown names.

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?

A single sentence, front-loaded with what is returned and then the accepted identifier forms. Every clause carries information; nothing is wasted.

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 one-parameter, no-output-schema lookup, the description covers what comes back (record plus source text) and how to address it. Only failure behavior for ambiguous or missing names is absent.

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% and the schema says only 'the qualified name,' so the baseline would be 3. The description adds genuine meaning beyond it: concrete qualified-name forms (`module.Type.method`, `module.Ability for Target`, `module.test:name`) and the bare-name uniqueness fallback.

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 resource ('One definition's record and its source text') and the qualifier that selects it, so the agent knows exactly what it retrieves. It does not, however, distinguish itself from siblings like library_lookup or chunks, which an agent must infer.

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 explains valid name formats but never says when to reach for this tool versus the ten siblings (library_lookup, project_map, chunks, etc.), nor any when-not condition. Nothing guides tool selection.

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