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

Goes well beyond the annotations: it discloses the per-call confirmation default and that it can be switched off, that the call reaches other people and should be confirmed with the user, that the login must be permitted to open chats for the account, and that a Cotlet API key with app access is required. openWorldHint=true is consistent with 'Reaches other people', so nothing contradicts.

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?

Front-loads the action and the scheduling option before the operational caveats, and every sentence carries information. The confirmation policy is stated twice ('you confirm each call' and 'confirm with the user before each call'), which is slight 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?

For a 3-parameter write-side tool with no output schema, the description covers purpose, scheduling, permissions, authentication and the confirmation obligation. An agent has everything it needs to decide whether and how to call it.

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 body, send_at and account_id are already documented in the schema; the description's mention that the message 'can be scheduled with send_at' merely restates it. 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?

States a specific verb and resource (send a message to a client in a chat) and adds the distinguishing scope 'now or at a set time' plus the surface it lands on (the account's chat, Communication tab). It does not name a sibling tool as an alternative route, so it falls just short of a 5.

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 by 'now or at a set time' and the requirement that the login be allowed to open chats for the account, but there is no explicit when-to-use versus a sibling (e.g. taxdome_send_invoice or request_documents) and no stated when-not-to-use.

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