retry_message

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

With no annotations, the description carries the burden and does well: it discloses the required `messages:write` permission, the message-state precondition (failed), the ownership precondition (sent by current agent), and the implicit side effect of sending a message. It omits what happens if the retry itself fails, whether duplicate sends are possible, and any rate-limit behavior.

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 behavioral constraints are front-loaded in the first two sentences with no filler. The trailing endpoint line and 'Tags: Conversations' are mildly redundant with structured metadata but harmless.

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 two-parameter action tool with no output schema, it covers permissions, preconditions, and endpoint semantics adequately. The notable gap is return behavior: an agent cannot tell whether the response returns the new message object, a status, or just success.

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 both path parameters are documented structurally and the baseline is 3. The PUT path template reinforces which identifier is the conversation and which is the message, but the description adds no further format or example guidance.

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 opens with a specific verb+resource ('Retries sending a failed message') and immediately narrows scope with 'in the specified conversation.' It does not name or contrast with a sibling such as send_message, so it stops short of full sibling differentiation.

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 gives a clear eligibility rule: only failed outgoing messages sent by the current agent can be retried. That implicitly excludes new sends and inbound messages, but it never explicitly points to send_message for creating new messages or says what to do for non-failed messages.

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