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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false. The description adds meaningful behavioral context: the channel lifecycle (opens on acceptance, closes on proof/cancellation), hard rate limits (500 chars, 50 messages, 10/min), and structured 409 error variants. It doesn't fully describe all failure modes or side effects, but it goes well beyond the annotations.

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 dense but every sentence earns its place: purpose, channel lifecycle, hard caps, return value, and error semantics. It is front-loaded with the core purpose and examples, then constraints, then return/error info. No fluff.

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 2-param tool with no output schema, the description covers the key behavioral context: when the channel is available, limits, return value, and error cases. It doesn't explicitly describe the success response shape beyond 'message id and remaining_messages budget', but that is stated. Minor gap: no mention of what happens if the task is not owned or if the worker is not assigned, but the 409s cover the main failure modes.

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 schema already documents both parameters. The description adds context about the body's purpose ('short coordination message', examples) and the task_id's scope ('owned task'), but doesn't add new syntax or format details beyond the schema. Baseline 3 is appropriate.

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 states a specific verb ('Send'), a specific resource ('a short coordination message to the worker assigned to an owned task'), and gives concrete examples. It is clearly distinguished from siblings like get_task_chat (retrieval) and make_offer/post_task (task creation/offers).

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 explicitly explains when the channel is open (worker accepted the offer) and when it closes (task leaves accepted/in_progress), and gives hard caps. It also implies when not to use it (only for logistics that matter, not general chatter). This is strong contextual guidance.

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