fable_block

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

Given no annotations, the description adds value by disclosing 'byte-identical — the exact original bytes,' indicating read-only, deterministic behavior. It does not mention permissions or error handling, but for a simple retrieval, this is nearly sufficient.

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, well-structured sentence with no filler. The core information is front-loaded: identity, purpose, and key characteristic (byte-identical).

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?

No output schema is provided, and the description does not explain the return format beyond 'byte-identical bytes'. It omits error scenarios (e.g., missing uuid) and any structural details of the record. The tool is simple, but completeness is lacking.

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?

With 0% schema coverage, the description must explain the uuid parameter, but only states 'by uuid'. It does not describe what the uuid represents (e.g., transcript record UUID) or its format, leaving the agent to infer.

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 it retrieves a single transcript record by uuid and returns the exact original bytes. It specifically differentiates from siblings like fable_thread and fable_recall by positioning itself as the tool for raw, unmodified data.

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 tells when to use this tool: to recover a specific tool result or turn that a summary or thread view elided. Implicitly advises against using it when a summary or thread view is sufficient, naming alternatives.

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