Send Message

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

With no annotations, the description discloses irreversible action, immediate delivery, and rate limits. This covers key behavioral traits beyond what schema provides.

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?

Description is concise with front-loaded purpose, followed by structured warnings and usage notes. Every sentence adds value, though slightly verbose with bullet points.

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 8 parameters, no output schema, and good schema coverage, the description provides sufficient context for an agent to call the tool correctly, including rate limits and usage patterns.

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%, providing thorough parameter descriptions. The description adds minor value by reiterating conversation ID usage but does not significantly expand on 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?

The description clearly states 'Sends an email message,' which is a specific verb+resource pair. It distinguishes from siblings like create_draft and draft_reply.

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?

Provides clear context for when to include or omit conversation ID, includes warnings about irreversible action and rate limits. Lacks explicit mention of alternatives but implies usage patterns.

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