chat_sendMessage

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

Annotations are absent, so the description carries the full burden. It simply states 'Sends a message' without disclosing thread-reply behavior (despite threadName in schema), potential errors for invalid spaces, or that the message is posted as the authenticated user. This is a write operation, but no additional behavioral context is provided.

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?

A single declarative sentence that communicates the core function in active voice with zero unnecessary words. It is front-loaded and easily scannable.

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?

While the schema fully documents parameters, the description lacks any mention of new-thread versus reply behavior, usage prerequisites, or return value. It is minimally viable but not comprehensive; the agent must infer important behavior from the schema alone.

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% with clear parameter descriptions (message text, space resource name, thread resource name to reply to). The description adds no extra parameter context, so the baseline score of 3 applies.

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 uses the specific verb 'Sends' with a clear resource ('a Google Chat space'), which immediately distinguishes this tool from sibling chat_sendDm (which targets DMs). The purpose is unambiguous and matches the tool name.

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 gives no guidance on when to use this tool versus alternatives like chat_sendDm or chat_setUpSpace, and doesn't mention prerequisites such as obtaining a valid spaceName via chat_listSpaces. The usage context is entirely implicit.

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