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

Annotations mark it as a non-read-only, non-destructive, non-idempotent write. The description adds genuinely new behavioral context beyond them: the draft is created empty, it returns the draft revision and app URL, and it does not launch the test. That last point is a useful boundary on a mutation tool.

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?

Two short, front-loaded sentences with no filler; the create action comes first and the downstream steps follow. The semicolon-joined fragments are terse to the point of slightly clipped grammar, but nothing is wasted.

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?

An output schema exists, so return values need not be detailed, and the description still notes revision and app URL. For a single-parameter setup tool the coverage is close to sufficient, with only the draft-vs-test terminology and sibling routing left thin.

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?

One parameter with 0% schema description coverage; the length constraints exist but carry no semantic meaning. The description's 'from a title' does tie the title parameter to the draft's naming, adding a little meaning, but nothing about format or rejection behavior.

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: create an empty draft from a title. The tool name (create_block_test) and the description's 'draft' framing create mild ambiguity about whether a test is being created, and no sibling (e.g. create_audience, prepare_test_block) is explicitly contrasted, but the core action 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?

It prescribes the follow-up sequence (add_task, set_test_audience) and an exclusion ('No launch'), which implies this is a setup step rather than a launch step. However, it never says when to choose this over create_audience or prepare_test_block, so the routing among siblings is left to inference.

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