ensure_block

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

No annotations are provided, so the description carries full burden. It fully discloses idempotent behavior, the 'created' field in response, and that the 'name' parameter is only applied on creation. All behavioral traits are explained clearly.

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?

Three well-structured sentences: first states preference, second explains idempotent behavior, third gives usage guidance and clarifies response field 'created'. Every sentence adds value without redundancy.

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 tool with 3 parameters, no output schema, and no annotations, the description covers all necessary context: idempotency, parameter behavior, usage recommendation, and response field clarification. No gaps remain.

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%, but the description adds crucial context for the 'name' parameter: 'Only applied when a new block is created; ignored when an existing block is returned.' This goes beyond the schema's basic description, informing agents of conditional 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?

The description clearly states the tool is for idempotent block creation, distinguishing it from add_block by explaining the behavior: returns existing block_id if block of given type exists, otherwise creates new. The verb 'ensure' and the phrase 'PREFERRED over add_block' make the purpose unmistakable.

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 states 'Use this for every block in your workflow so re-runs and retries never produce extra blocks.' This gives clear, actionable guidance on when to use this tool instead of add_block, and explains the benefit of idempotency.

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