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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description doesn't need to repeat safety info. It adds semantic context about the content of runs (e.g., actual vs planned length) but doesn't disclose any further behavioral traits such as pagination or return format. Given the annotations cover the safety profile, a 3 is appropriate.

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 two sentences, gets straight to the point, and front-loads the primary purpose. The second sentence about the account requirement is slightly redundant given the token parameter but not wasteful. It avoids unnecessary detail and is appropriately brief.

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 simple read-only list operation with full schema coverage and safety annotations, the description provides sufficient context: what it lists, the use case, and the account requirement. It doesn't specify the return format, but since there's no output schema, agents can reasonably infer a list of run objects. Minor gap but not critical.

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?

The input schema provides full descriptions for both parameters (100% coverage), so the description adds no extra meaning. The description does not elaborate on token requirements or program_id handling beyond what the schema already states. Baseline 3 applies because the schema handles parameter documentation.

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 action 'List recorded runs' and specifies the resource 'of a saved program' with the kind of information returned (when, how it ended, actual vs planned length). It distinguishes itself from siblings like list_public_runs (public runs) and load_run (single run) by focusing on the user's own saved program runs.

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 provides a concrete use case, 'For how long did this take last time?', and notes the prerequisite of having the user's Rhylthyme account. It implies this is for personal runs rather than public ones, but does not explicitly name alternatives like list_public_runs. Still, the usage context is clear enough for an agent to decide when to call it.

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