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

The description adds real context beyond the annotations: the note lands in the request's thread, is visible to the approver, is length-limited ('short'), and explicitly does not count as an approval — which preempts the dangerous misreading. It does not address the residual tension with readOnlyHint=true (the call still creates a visible message) or whether notes are editable/retractable, and it leaves delivery/notification behavior unexplained.

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 front-loaded sentence with the resource and audience first and the crucial non-approval caveat last. 'from Rithmo's app' is slightly incidental but does clarify provenance; nothing is padded.

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 three-parameter tool with no output schema and no schema descriptions, the description covers the purpose, the audience, and the key semantic guarantee, but it is thin on identity/authorization (agent_key) and on what the caller gets back or how the note is rendered. Adequate, not 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 description coverage is 0%, so the description must carry all parameter meaning. It effectively explains 'text' ('short note', content of what happened) and implies 'approval_id' via 'an approval request's thread', but 'agent_key' is never mentioned in the description or the schema, leaving an agent with no guidance on that required-for-auth style parameter.

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?

States a specific verb and resource: post a note to the approver in a specific approval request's thread, with the note's content scoped ('what happened to the action, or an answer to their question'). It distinguishes itself from the approval action via 'It never counts as an approval', but it never names the close sibling report_action_outcome, so an agent must still infer the split between a free-form note and a structured outcome report.

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?

Usage is implied rather than stated: put status updates or answers to the approver's questions here. There is no explicit when-not-to-use and no named alternative, even though report_action_outcome and approve_from_chat are obvious adjacent choices an agent would need to choose between.

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