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

With no annotations, the description carries the full burden, and it discloses only one genuine behavioral trait: it will never grade a child. That is a useful boundary, but nothing is said about what the tool returns, whether it reads or writes state, or how it relates to the other coach tools. For a tool with zero annotation coverage this is a substantial gap.

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 short sentence, front-loaded with the scope tag and the boundary constraint, with no filler. Its brevity is appropriate, though the phrasing is cryptic rather than economical.

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 annotations, no output schema, and a zero-parameter schema, the description is the only source of information — and it leaves the return content, the read/write nature, and the tool's place among the coach_* family unspecified. It is not yet sufficient for confident invocation.

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?

The tool takes no parameters, so per the rubric the baseline is 4. There are no arguments whose meaning could be clarified or obscured by the description.

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 restates the tool's own name ('Coach — what it does') without naming a concrete verb or the artifact it returns. It never distinguishes itself from the six closely-named siblings (coach_overview, coach_next, coach_recommend, coach_subjects, coach_unit, coach_mastery), so an agent cannot tell which coach_* tool to pick. Only the boundary clause ('never grades a child') hints at actual content.

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 bracketed '[WALK · internal]' tag implies an internal walkthrough context, but there is no statement of when to call this versus coach_overview or coach_recommend, and no preconditions or exclusions. The agent is left to infer usage entirely from the name.

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