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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the mutation profile is covered structurally. The description adds genuine value with the scheduling precondition, but omits what happens if the precondition is unmet (error? silent no-op?) and gives no sense of irreversibility.

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 sentence with the resource first and the constraint second; zero filler and nothing redundant. Optimal length for a one-parameter mutation.

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 one-param tool with rich annotations and no output schema, the description covers the core constraint but leaves the failure mode and post-cancel state (what the push becomes) unstated. Adequate, not complete.

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 100% and the single 'id' parameter is documented in-schema as a msg_... string. The description contributes nothing about the identifier beyond what the schema already states, so baseline 3 applies.

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+resource ('Cancel a push') and scopes it to pushes that are 'scheduled and has not started sending', which cleanly separates it from send_push/get_push/list_pushes siblings. It does not explicitly name a sibling alternative, but no sibling overlaps enough to create ambiguity.

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?

The precondition ('scheduled and has not started sending') implicitly tells the agent when the tool is applicable, which is more than nothing. However, it never says what to do when the push has already started, nor names any alternative path, so the agent must infer failure behavior.

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