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

Annotations already flag destructiveHint=true, but the description adds the non-obvious and critical trait: the caller must supply full program data and merge edits, implying omitted fields are dropped/overwritten. That is real behavioral value beyond structured fields. It omits permission requirements and recovery options, so not a 5.

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 short sentences: purpose, trigger, then the full-payload requirement. Front-loaded and every sentence earns its place. The final sentence is dense enough that it could be split for readability.

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?

An output schema exists, so return values need no explanation, and annotations cover the safety profile. What remains for a 10-parameter destructive mutation — the read-then-merge workflow — is exactly what the description supplies.

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 0%, so the description carries the burden. It names six of the ten fields (duration_in_weeks, workouts_per_week, goal_ids, workout_ids, visibility, difficulty) but says nothing about name, team_id, description, or program_id, and omits constraints like the two-goal cap and the two-workout minimum. Partial compensation only.

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?

States a specific verb+resource ('Updates an existing program') and enumerates the mutable facets (duration, workouts per week, metadata), which clearly separates it from create_program and update_workout. It does not explicitly name a sibling as the alternative, so it stops short of a 5.

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?

'Use when the user wants to set duration, workouts per week, or edit program metadata' gives a concrete trigger condition, and the description names the prerequisite read tool (get_team_program) needed before calling. No when-not guidance or explicit alternative tool is offered, so 4 rather than 5.

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