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

Annotations already declare readOnlyHint=true and idempotentHint=true, lowering the bar. The description adds genuinely useful behavioral context beyond annotations: the ~300 token cost estimate, the sections widening behavior including the 'all' shortcut, and the explicit statement of what is NOT returned (skill instructions). No contradiction with 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?

Three sentences, zero filler. The opening sentence establishes purpose, the second adds the cost rationale and the sections mechanic, the third disambiguates from load_skill. Each sentence is front-loaded and 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 metadata-retrieval tool with an output schema, 3 documented params, and strong annotations (readOnly, idempotent), the description covers purpose, usage context, cost behavior, section semantics, and sibling differentiation. The output schema handles return values, 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 all 3 parameters are documented. The description adds value beyond the schema by explaining the sections param usage pattern ('Pass sections to widen, or sections:[all]'), which the enum list alone doesn't convey. It also contextualizes slug examples indirectly. Slightly above baseline due to the practical 'all' guidance.

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 uses a specific verb+resource ('Metadata for one skill or journey') and enumerates exact content (definition, when to use, when not to, related slugs). It explicitly distinguishes itself from siblings with 'This does not return the skill instructions — load_skill does,' differentiating clearly from load_skill and get_journey.

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 when-to-use guidance: 'cheap (~300 tokens) so you can check a candidate before committing context to it' clearly frames the use case. It also names the alternative (load_skill) for skill instructions, giving concrete when-not-to direction, and explains how to widen results with sections.

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