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

Beyond the annotations (readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false), the description adds meaningful behavior: the message lands in a human-readable chat, no automated assistant replies, and 'any connected account can send it' warns that the sending identity is not constrained. It still does not say what happens afterward (ticket, confirmation, response channel).

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 short sentences, front-loaded with the core action and no filler. The closing sentence is slightly clipped ('text is what is needed...') but still carries information, so nothing is wasted.

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 single-parameter write tool with no output schema and annotations already covering the safety profile, the description covers the action, the expectation of a human respondent, and what to put in the parameter. Only the post-submission behavior (confirmation, follow-up) is left unstated.

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 schema gives no help on 'text'. The description compensates by specifying what the text should contain ('what is needed and what was already tried'), which is real guidance an agent could not get from the schema alone.

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 first sentence gives a specific verb and resource ('Writes a message into this user's Support chat for a person to read'), which separates it from the read-only sibling read_support and from the generic send_message by naming the Support channel. It also rules out the help-search path by stating Support's own assistant does not answer, but it never names a sibling tool outright, so an agent must infer the routing.

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: the message is directed 'for a person to read', which signals escalation to human support, and 'text is what is needed and what was already tried' hints at the situation in which to call it. No explicit when-not conditions or named alternatives (search_help, read_support, request_speak) are given.

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