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

Annotations already declare readOnly/destructive/idempotent, so 'Changes nothing, contacts nobody and uses no AI' is partly reinforcement, but it usefully rules out side effects like outreach that an agent might otherwise fear. The rule enumeration (banned phrases, per-kind length limits, follow-up format, placeholder handling) is genuine added context beyond the annotations, though the output shape is only sketched as 'each issue'.

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?

The core purpose is front-loaded in the first sentence and the trailing sentences clean up behavior and the placeholder caveat. It is slightly dense with parenthetical detail but no sentence is filler.

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 does the necessary work by saying it 'Returns each issue so it can be fixed,' and it covers side-effect concerns and per-kind rules. A brief note on whether the check is strict/blocking or advisory would make it fully complete.

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 baseline is 3, but the description adds real meaning: 'kind' determines which limit applies (characters for the note, words for a follow-up), and it clarifies that template placeholders like {{first_name}} are permitted rather than flagged. That is interpretation guidance the schema alone does not convey.

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?

States a specific verb ('Check') and resource ('one connection note or follow-up you have written') and then enumerates exactly what is validated: banned phrases, length limits, follow-up format, nonexistent placeholders, and {{signal}}. This is concrete enough that an agent can distinguish it from any sibling tool without opening the schema.

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?

Frames the usage clearly as a pre-save check ('against the same rules ZenMode enforces when it is saved'), which tells the agent when to reach for it. It does not name an alternative tool or state exclusions, so it stops short of the explicit when/when-not bar.

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