Skill costs (ranked)

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

With no annotations provided, the description carries the full burden. It discloses a key trait: the described costs are for always-loaded descriptions, not optional invocations. It also implies read-only behavior. However, it doesn't detail output structure or whether the list is sorted descending (though 'top' implies it). Reasonable but not exhaustive.

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?

Two concise sentences, front-loaded with the main purpose and followed by actionable insight. No wasted words; every phrase earns its place.

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 query tool with no output schema, the description sufficiently explains what it returns (ranked skills with token costs). It does not explicitly state whether token counts are included or the sort order, but 'top of this list' implies descending order. Most users would find it complete enough.

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 100%, with both parameters (limit, filter) having descriptions in the schema. The tool description adds no parameter-specific information, so it relies on the schema. Baseline 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 clearly states the tool ranks skills by the token cost of their always-loaded descriptions, with a specific verb ('ranked') and resource ('skills'). This distinguishes it from sibling tools like duplicate_skills (which finds duplicates) and context_budget (which measures overall budget).

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 says 'The top of this list is where trimming pays off most,' which gives clear guidance on when to use the tool (to identify costly skills for trimming). While it doesn't name alternatives or exclusions, the use case is strong and implied.

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