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

Annotations already establish readOnly/idempotent/non-destructive, so the bar is lower; the description still adds real behavior: default 5 items per class, a maximum of 20, and an explicit statement that participants are not ranked. It stops short of describing output shape or pagination, so not a 5.

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 dense sentences, usage condition front-loaded, then alternatives, then return-size constraints. No filler and nothing redundant enough to cut.

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?

With no output schema, the description carries the return-value burden, and it only partly does: item count and the non-ranking property are covered, but what a 'gap' item contains and what 'per class' means are left unresolved for a 17-sibling tool set.

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% and all three parameters are documented in-schema, so the baseline is 3. The description's mention of the 5-default/20-max bound largely restates the limit parameter and adds 'per class' nuance but no semantics for model_claim or provider_claim beyond what the schema already says.

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 defines the target condition ('mechanically low-diversity or caller-absent public trails') but never states an explicit verb or what the tool actually returns — 'gaps' remains undefined. It is distinguishable from siblings, but the agent must infer that this is a read that surfaces gap-class items.

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?

Explicitly names three alternative siblings (commons_opportunities for mixed actionable work cues, commons_disputes for contested targets, commons_metrics for corpus-wide measurements) and the condition that selects each. This is exactly the when/when-not routing an agent needs.

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