export_block

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

With no annotations, the description carries the disclosure burden. It reveals the tool is non-destructive (downloads), has a dependency on a prior upload, and produces files in specific formats (zwo, etc.). It does not explicitly state side effects or permission requirements, but the nature of the operation is clear.

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?

The description is organized into three focused paragraphs: purpose, usage context, and file placement. Each section provides necessary information without redundancy, though the phrase 'workout files' appears twice. It is front-loaded with the core purpose.

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?

Given the tool has 5 parameters and an output schema, the description covers the key prerequisites (upload_block first), the main use case (alternative to integration), and post-export steps (placing .zwo files). It does not explain the output schema or error handling, but the output schema exists to cover return values.

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%, so the baseline is 3. The description does not add parameter-specific meaning beyond the schema; the schema already explains dates, output_dir, and file_format. The description's mention of .zwo placement adds context for output use, but not parameter semantics.

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 opens with 'Downloads an uploaded block as workout files,' which clearly states the verb (downloads), resource (uploaded block), and output (workout files). It differentiates from siblings like upload_block and list_block by emphasizing the export nature and positioning it as an alternative to the intervals.icu integration.

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 description explicitly states a prerequisite: 'The workouts must be in the calendar first — run upload_block before.' It also provides the use case: 'useful when Zwift runs on a device where the integration is unavailable,' which clarifies when to choose this tool over the integration. It also includes concrete file placement instructions.

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