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

Annotations already declare idempotentHint, destructiveHint=false and openWorldHint, so 'idempotent' in the description earns no credit. The description does add useful effect context: that the message steers an active task or resumes a metered one after expiry. However, it says nothing about failure modes, permission requirements, or what happens to the current task on delivery, so behavioral coverage remains thin.

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 tight sentence with the action front-loaded and the effect trailing. No filler or repetition beyond the 'idempotent' overlap with annotations, which is minor.

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 mutating tool with three required, 0%-documented parameters and no output schema, the description should explain messageId's role as the idempotency key and the threadId target. Neither appears, so an agent must guess at call-correctness details.

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 coverage is 0% and the description explains none of the three required parameters. Crucially, it never ties 'messageId' to the idempotency behavior or explains 'threadId' targeting, leaving the most error-prone parameter undefined in both schema and prose.

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 ... message to a Dex thread') plus the effect ('steering its active task or resuming a metered task after expiry'). This clearly distinguishes it from siblings like devtune_start_dex_conversation or devtune_get_dex_events. It stops short of naming alternatives in the text, but the scope is unambiguous.

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?

Implies the usage condition ('steering its active task or resuming a metered task after expiry') but does not name an alternative tool or state an explicit when-not. An agent can infer when it applies, but activation guidance is only partial.

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