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

Description adds behavioral traits beyond annotations: 'Empty or filtered messages are dropped silently (sent:false)'. It also emphasizes casual, brief tone. Annotations already indicate write and open-world, but the description adds practical usage details without contradiction.

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 concise (4-5 sentences), front-loads the purpose, and uses imperative and negative statements efficiently. Every sentence adds value without redundancy.

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 the tool's simplicity (2 required params, no output schema, no enums), the description covers purpose, usage constraints, parameter semantics for text, and behavioral details like silent dropping. It could mention the meaning of 'space' more explicitly, but overall it is reasonably complete.

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 0%, so description must compensate. It effectively explains the 'text' parameter (one short line, casual, no formatting) but does not explicitly describe the 'space' parameter beyond its existence. This provides moderate added meaning.

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 tool's purpose: 'Talk in the world like a real person' and specifies it outputs 'ONE short line' as a 'quick callout'. This distinguishes it from sibling tools which perform different actions like building, moving, or memory operations.

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 'DO NOT' instructions excluding reports, recaps, status updates, narration, and agent IDs. While it doesn't explicitly list when to use (it's obvious for speaking), the exclusions are clear and helpful.

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