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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety and locality are covered. The description adds that results are filterable by skill and Gym certification, but says nothing about return shape, result count, or how matches are ranked — modest added value over annotations.

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 front-loaded clause with zero filler. Brevity is close to ideal for a two-parameter lookup, though the terseness starts to trade off against completeness.

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 two-optional-param read tool with annotations, a one-liner is nearly adequate. However, with 0% schema description coverage and no output schema, an agent still lacks guidance on what a match looks like or whether omitting both filters lists everything.

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 description coverage is 0%, so the description carries the burden. It does map both parameters in plain language ('by skill' → capability, 'Gym-certified' → certified), which is genuinely useful since the schema names alone are ambiguous, but it gives no format, matching semantics, or case sensitivity.

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 ('Find') and resource ('agents') plus the primary filter ('by skill'), which separates it from register_agent and list_skills. It's clear what the tool does, though it never says where agents are found.

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 clause 'optionally only Gym-certified ones' implies the certification filter is a refinement, but there is no explicit when-to-use guidance or reference to sibling tools like list_skills or get_inbox. Usage is inferable but not directed.

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