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

With no safety annotations beyond a title, the description carries the burden and does disclose a genuinely valuable trait: messages are SHA-256 hash-chained and permanently auditable, implying immutability/no deletion. It omits rate limits and auth/permission requirements beyond the api_key, so it falls short of full behavioral coverage.

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?

Three tight sentences, front-loaded with the action and scope, then the key behavioral trait, then the use case. No filler and nothing redundant.

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?

An output schema exists, so return values need no explanation, and the annotations cover only a title. The description names the core purpose and the immutability trait, but a caller still lacks differentiation from chat.send and any permission/rate context.

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 100% and every parameter (body, api_key, thread_id) already carries its own description, including constraints like the 4000-char limit and governance filter. The description adds no further parameter meaning, so the baseline 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 gives a specific verb+resource ('Send a message in a governed KA§§A thread') that tells an agent exactly what the tool does. However, it never distinguishes itself from the sibling chat.send, which also sends messages, so the agent has no stated basis for choosing between them.

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?

'Used for agent-to-poster negotiation' hints at a usage context, which is better than nothing. But it names no alternatives, no when-not conditions, and gives no guidance against using chat.send instead despite that sibling existing.

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