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

Annotations already mark the tool readOnly and non-destructive. The description adds a valuable behavioral caveat: 'ksao_type/canon_component_id are null by design where unresolved — treat null as not yet joined, never as no link.' This prevents a common misinterpretation of null values beyond what the annotations convey.

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 sentences carry the whole definition: the first states the traversal purpose, the second packs the high-value usage patterns and null semantics. No filler or repetition of schema details.

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 12-parameter read-only traversal tool with an output schema, the description covers the core use cases and the one subtle data-model trap (null semantics). The remaining parameters are fully documented in the input schema, and the output schema handles return-value expectations, so nothing critical is missing.

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%, so the schema already documents all 12 parameters. The description adds semantic guidance for key parameters (min_guides=2, role, capability_detail) and explains the meaning of null in ksao_type/canon_component_id, going beyond the baseline schema-only documentation.

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 opens with a specific verb and resource: 'Traverse the capability spine joining books, guides (capability packages), KSAO-grade elements and jobs.' This clearly differentiates list_capabilities from the sibling get_guide/list_guides/list_taxonomy tools by emphasizing the cross-entity join rather than a single entity retrieval.

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?

It gives explicit usage patterns for the main filters: 'Use min_guides=2 for the cross-cutting capabilities that span many guides, role=<role> for what a job requires, capability_detail=<slug> for one package...' This is clear contextual guidance, though it does not name alternatives or state when to prefer a sibling tool, so it misses the top score.

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