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

Annotations already establish readOnly, idempotent, closed-world and non-destructive, and the description adds genuinely useful behavior: data travels in the URL fragment with nothing stored, logo_url is never fetched server-side, and a claim_url exists per design because the human must sign up in the app. It does not discuss failure modes (bad sector value, unreachable logo, missing colour) which would round this out.

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 lead sentence front-loads the trigger and the core action, and the second sentence enumerates the concrete returns, which is the right order for an agent deciding whether to call it. It is dense and the long lists of clients, features and sectors-to-parameter mappings make it heavier than necessary, but almost every clause adds decision-relevant information.

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?

This is a 17-parameter, no-account generator with no output schema, and the description compensates by spelling out every return: one preview_url rendering all designs, a claim_url per design, paste-ready HTML, install options with pricing, and present_to_user. Combined with the no-storage and no-server-fetch notes, an agent has enough to call it and to explain the result to a user.

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% and the per-field descriptions are already rich, so baseline is 3. The description contributes a little extra by grouping the signals it consumes (person, company, brand colour, logo URL, website, socials, department, sector, team size) and by explaining that cta and layout choices are defaulted from the playbook for the role and sector, but it gives no per-parameter guidance beyond that.

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 names a concrete action (builds 3–4 professional designs) and resource (email signatures) and even declares the entry point: 'Start here when a user asks for an email signature.' It scopes the tool against the sibling create_signature by emphasizing no-account generation with a claim_url where the human later signs up, so an agent can pick it without opening either 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?

'Start here when a user asks for an email signature' is an explicit when-to-use rule, and the claim_url explanation implies the handoff to sign-up. What is missing is a negative case — nothing says when to prefer get_signature_playbook, list_layouts, quote_price or create_signature directly instead of this generator.

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