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

Annotations already establish readOnly, non-destructive and closed-world, so the bar is lower. The description adds real behavioral value beyond them: every email comes with subject, send day and body, a note on inputs the caller omitted is returned, no placeholder is left in a body, and no statistic is fabricated. It does not say whether output is persisted or how long sequences run, which keeps it short of 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?

Three sentences, front-loaded with the purpose, then the inputs, then the output shape and guarantees. Every clause carries information; nothing repeats the schema verbatim or pads the definition.

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 12 parameters, 3 required and no output schema, the description needs to sketch the return shape, and it does so (subject, send day, body, omission note). It is complete enough to call correctly, though it leaves open whether sequence length varies by type and how tone interacts with the generated copy.

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 the baseline is 3, but the description adds meaning by grouping the inputs into what you supply (persona, stage/objective, solution, pain point, value proposition, proof, ask) and by implying the tool reports back what was not given. Tone, sender_context and your_sector are not addressed in prose, so the gain over the schema is modest rather than complete.

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 states a concrete verb+resource: it produces an email sequence, with each email's subject, send day and body. It also scopes the purpose to opening or restarting a conversation, which separates it from siblings like proposal_section_writer or discovery_question_bank. It never names a sibling explicitly, so differentiation is inferred rather than stated.

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?

It gives clear context for use: prospecting, nurture, follow-up or re-engagement conversations, and lists the inputs that select the right sequence. There are no explicit exclusions or named alternatives for adjacent tasks such as post-demo or proposal follow-up, so the agent must infer boundaries from the schema enum.

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