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

Annotations already mark the tool as read-only and non-destructive, and the description adds important behavioral nuance: '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 and goes beyond what 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?

The description is compact and front-loaded: purpose first, then usage patterns, then a critical caveat. Every sentence earns its place and there is no filler or repetition of schema content.

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, fully optional query tool with an output schema and read-only annotations, the description covers the main invocation modes and flags the most likely misinterpretation. The output schema handles return-value details, so nothing essential 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 baseline is 3. The description adds genuine value by explaining how to use min_guides, role, and capability_detail for specific intents, plus the null semantics around ksao_type/canon_component_id. It doesn't re-explain every parameter, but it sharpens the most important ones beyond the schema text.

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 a specific verb and resource: 'Traverse the capability spine joining books, guides (capability packages), KSAO-grade elements and jobs.' This clearly distinguishes the tool from sibling tools like list_guides or get_guide by framing it as a cross-entity traversal rather than a simple list or detail fetch.

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 gives explicit invocation patterns for key modes: 'Use min_guides=2 for the cross-cutting capabilities', 'role=<role> for what a job requires', and 'capability_detail=<slug> for one package with its elements and books hydrated.' It lacks explicit when-not-to-use guidance or named alternatives, but the provided context is strong and actionable.

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