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

Annotations declare the safety profile (write, idempotent, non-destructive) but not the matching semantics. The description adds real behavior beyond them: case and repeated-space insensitivity, no substring matching inside longer words, and the concrete idempotency outcome ('An identical phrase returns the existing row') which fleshes out idempotentHint=true. No auth or limit context, 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?

Four short sentences, front-loaded with the action and its downstream effect, then matching rules and idempotency. Nearly every sentence earns its place, though the matching-detail sentence could be tightened slightly.

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?

An output schema exists so return values need no explanation, and annotations carry the safety profile. Still, for a write tool with 0% schema coverage the description leaves the 'note' parameter and input constraints undocumented, so an agent lacks full invocation detail.

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% across three parameters, and the description compensates only partially: it explains the semantics of the phrase value (normalization, no substring match) but says nothing about the optional 'note' parameter or how brandId scopes the record. The minLength 2 / maxLength 200 constraints are left entirely to the schema.

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?

Specific verb + resource ('Store a phrase the brand forbids') with the scope constraint that the phrase is brand-scoped. It also names the sibling that consumes the data (check_brand_copy) and implicitly contrasts with remove_banned_phrase via the verb 'Store'.

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 first sentence implies the trigger (adding a phrase the brand forbids) and the second explains the downstream consequence in check_brand_copy, which is useful context. But there is no explicit when/when-not guidance and no routing versus remove_banned_phrase or save_approved_claim.

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