draft_reply

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

With no annotations provided, the description fully bears the burden. It discloses that the tool only drafts (never auto-sends), marks certain fields as untrusted ('provenance:untrusted-email-body'), and explains that the response's safety block restates hard-stops. This is sufficient behavioral context for an agent.

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 description is short (three sentences) and front-loads the primary purpose. The safety warnings are necessary but add some length. Each sentence provides actionable information, with no wasted words.

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?

Given 12 parameters and no output schema, the description covers key behavioral aspects: drafting nature, auto-send prohibition, safety rules, and untrusted data handling. It lacks details on return format, but for a drafting tool, the core constraints are well-communicated.

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 58%, so the description adds value beyond the schema by explaining untrusted data provenance and the meaning of 'knownSender' (first-contact hard-stop). However, for parameters like 'focus', 'verbosity', 'receivedAt', the description offers no additional semantics. It compensates partially but not fully.

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 explicitly states 'Draft the reply that discharges a commitment owed in a message' with verb 'draft' and resource 'reply', and distinguishes from siblings by mentioning 'DRAFT ONLY — never auto-sent'. No sibling tool is for drafting replies, so it is clearly differentiated.

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 description provides explicit conditions for use: discharging a commitment. It also lists refusal conditions (money, changed-banking, first-contact, decision, injection) with 'human-only' constraint. While it doesn't explicitly mention when to use alternatives, the safety rules imply when not to use. Overall, clear context for appropriate use.

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