send_message

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

With no annotations provided, the description carries full burden but offers minimal behavioral insight. It mentions a return value ('Confirmation message with sent message details'), which adds some context beyond the basic action. However, it lacks critical details like authentication requirements, rate limits, error conditions, or whether the operation is idempotent—significant gaps for a tool that performs a write operation.

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 brief and front-loaded with the core purpose in the first sentence. The second sentence about returns is useful but could be integrated more seamlessly. Overall, it avoids unnecessary verbosity, though slight structural improvements could enhance clarity.

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 tool with 5 parameters, 0% schema coverage, no annotations, and no output schema, the description is insufficient. It covers the basic action and return hint but omits parameter explanations, behavioral nuances, and differentiation from siblings. Given the complexity and lack of structured support, more comprehensive guidance is needed.

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 0%, so the description must compensate but fails to do so. It provides no information about the 5 parameters (e.g., what 'service' refers to, how 'space_id' is obtained, the purpose of 'thread_key'), leaving them entirely undocumented. This is inadequate given the parameter count and coverage gap.

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 the action ('sends a message') and target resource ('to a Google Chat space'), which is specific and unambiguous. However, it doesn't differentiate from sibling tools like 'send_gmail_message' or 'get_messages', which would require explicit comparison to achieve a perfect score.

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?

No guidance is provided on when to use this tool versus alternatives like 'send_gmail_message' or 'search_messages'. The description only states what it does without context about appropriate scenarios or prerequisites, leaving the agent to infer usage.

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