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

Annotations declare readOnlyHint=false, destructiveHint=false, and idempotentHint=true, but the description goes further: it says the Post and its text are preserved in the library, that already-draft Posts are reported unchanged rather than erroring, and that four specific states produce an error. That is real behavioral context beyond the annotation set, not a restatement.

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?

Five short sentences, each carrying distinct load: state transition first, then data-preservation and the inverse tool, then idempotency, then failure states, then id discovery. The most important fact (what the tool does) is front-loaded with no filler.

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 mutation with no output schema, the description covers everything an agent needs: the transition, non-destructive semantics, idempotency, error conditions, and id sourcing. There is no meaningful gap remaining.

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 schema already specifies the full Post id (not the 8-character prefix) sourced from list_scheduled or schedule_post. The description's 'Find the id with list_scheduled' largely duplicates that. With the schema doing the heavy lifting, baseline 3 is appropriate.

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 scheduled Post) and the exact state transition it performs: from scheduled/ready back to draft with scheduled time cleared. It also names the sibling tool (schedule_post) that performs the inverse, so the agent can distinguish it without opening either schema.

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?

Explicitly covers when to use (Post is scheduled or ready), when not to (publishing, posted, or failed returns an error), how to find the required id (list_scheduled), and how to undo the effect (schedule_post). Alternatives and preconditions are all named rather than inferred.

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