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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the destructive nature is known. The description adds minimal extra context—it only says 'Delete a specific chat message', which doesn't go beyond the annotations. It could have mentioned permanence or that only that message is affected, but those are already implicit. Thus it adds little beyond what structured data provides.

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 efficient: three short sentences that front-load the action, then give usage context and the prerequisite. Every sentence earns its place with no fluff, making it easy for an agent to parse quickly.

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 simple single-parameter tool with annotations covering destructiveness and no output schema, the description covers the action, usage context, and how to obtain the ID. It does not discuss error handling or return values, but those are not critical given the tool's simplicity and absence of an output schema. Overall, it is complete enough for correct invocation.

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?

The schema already describes the messageId parameter and says to get it from chat-list. The description repeats this instruction, adding no new semantic meaning beyond what the schema provides. Since schema coverage is 100%, the baseline of 3 applies, and the description does not significantly enhance parameter understanding.

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 clearly states the action (delete), the resource (chat message), and the specificity (by ID). It also conveys the use case (remove erroneous messages, clean up chat), which distinguishes it from siblings like chat-clear or chat-update without explicitly naming 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?

It provides clear context for when to use the tool ('remove erroneous messages or clean up chat') and gives a prerequisite ('Use chat-list FIRST to find the message ID'). However, it does not explicitly state when not to use it (e.g., for bulk deletion use chat-clear), so exclusions are only implied.

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