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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and non-destructive behavior, so the safety profile is covered. The description adds genuine behavioral context by disclosing that it returns a single page and how to continue, which is beyond what the annotations say.

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?

A single compact sentence that front-loads the resource scope and follows with the pagination instruction. No words are wasted.

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 no-annotation-gap read tool with one cursor param, the description covers pagination but leaves key questions open: what a 'change' contains, what the response shape is, and what 'public V1' implies. With no output schema, this is the minimum viable level.

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 0% — 'since' is a bare integer with no documented meaning. The description compensates by explaining that the value comes from a prior response's 'next_since' field, which gives the parameter real semantic role beyond the schema's numeric bounds.

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 identifies the resource as a 'public V1 changes page', which distinguishes it from the fires/clearing/status siblings, but the verb is missing — an agent must infer that it retrieves or lists changes. The purpose is inferable but not stated with a specific action.

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 only guidance is pagination mechanics ('pass next_since as since to resume'), not when to use this tool versus yac_list_fires, yac_status, or others. There is no statement of context, prerequisites, or exclusions.

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