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

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description reinforces this with 'Read-only' and 'Does not write a report', which rules out a side-effect the agent might otherwise assume from a 'check' tool. It also discloses where the data comes from ('public catalog and note Markdown') and the exact threshold logic, adding real behavioral value beyond the 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 tight sentences with the core predicate front-loaded and no filler. The reference to scripts/stale-check.mjs is the weakest element since it points at an external file rather than being self-contained, but it does convey intent economically.

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?

There is no output schema, so the description should ideally say what a result looks like (list of notes, counts, threshold applied per note), and it does not. The threshold rules and read-only nature are covered, but the return shape and the role of the 'today' parameter remain gaps for a zero-required-parameter tool.

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% for three parameters, so the description carries the burden and only partially meets it: the 90-day and 365-day rules implicitly explain 'days' versus 'sensitive_days' and their defaults, but 'today' is never mentioned and no parameter is named directly. The mapping requires inference rather than being stated.

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 opening sentence names the resource (notes) and the exact condition that selects them (past their checked_on threshold), which is specific enough to distinguish it from siblings like list_notes or search_notes. It stops short of naming an alternative tool explicitly, but the predicate 'stale' is unambiguous.

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?

Usage is implied by the domain rules (auditing note freshness against a threshold), and 'Does not write a report' quietly signals it is an inspection tool rather than a generator. There is no explicit when-to-use/when-not guidance relative to list_notes or search_notes, so the agent must infer the selection criteria.

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