hey_send_email

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

With no annotations, the description carries the full burden. It discloses that sending is immediate (no draft stage) and returns {success, error?}. However, it lacks details like authentication requirements, rate limits, or what happens on failure beyond a generic error. This is adequate but not rich.

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 two sentences long, front-loads the core action and return format, and then provides usage alternatives. Every sentence adds value; 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?

For a simple email send tool with 4 parameters, 100% schema coverage, and no output schema or nested objects, the description is complete. It explains the immediate behavior, return type, and when to use alternatives. No additional context is necessary.

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 100%, so the baseline is 3. The description does not add semantic meaning beyond what the schema already provides (e.g., 'HTML supported' for body is repeated). No extra parameter guidance is given.

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 'Send a new email immediately (no draft stage)', identifying the verb (send) and resource (email). It explicitly distinguishes from siblings by mentioning 'use hey_reply for thread responses, or hey_forward to share existing emails with new recipients'.

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 usage guidance: 'Use for standalone outbound messages; use hey_reply for thread responses, or hey_forward to share existing emails with new recipients.' This tells the agent exactly when to use this tool versus its alternatives.

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