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

Annotations already declare readOnlyHint/idempotentHint/non-destructive, so the safety profile is covered; the description still adds real value by stating 'Saves nothing ... Nothing is saved either way' even with accept, and by disclosing the auth requirement ('Needs the user's Rhylthyme account'). It stops short of describing rate limits or failure behavior.

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 sentences, front-loaded with the action and its statistical defaults, followed by side effects and the account requirement. Dense but every clause carries information; no filler.

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 7-parameter, zero-required tool with nested objects and no output schema, the description covers the core behavior, the non-persistence guarantee, the auth need, and hints at the return contents (evidence per step, effect on total length). It could say more about how program vs program_id vs history interact, but the essentials are present.

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%, so all seven parameters are already documented in the schema. The description's mention of accept returning the calibrated program and of the median/P10–P90 basis adds mild meaning but largely repeats the schema, so the baseline of 3 applies.

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 gives a specific verb+resource ('Propose durations for a saved program from its recorded runs') and even specifies the statistical method (median default, P10–P90 range, at least as wide as the author's). It is clearly distinct from siblings like validate_program or review_program, but it never names or contrasts an alternative explicitly.

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?

Usage is implied by the verb and the input set (a saved program plus its runs), and the 'Saves nothing' clause signals the preview-style intent. However there is no explicit when-to-use/when-not statement and no routing to alternatives such as review_program or load_run.

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