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

Annotations already declare readOnlyHint=false and destructiveHint=false, so safety is covered, but for a partial-update mutation the description never says whether omitted fields are preserved or cleared, nor whether the day must belong to the caller's program. It adds essentially nothing behavioral beyond what the annotations state.

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 ten-word sentence, front-loaded with the action verbs and free of filler. It is efficiently built but so terse that brevity shades into under-specification.

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 an 8-parameter mutation tool with 25% schema coverage and no output schema, the description leaves major gaps: partial-update semantics, the status enum's effect, and whether moving a day can cross weeks. An agent could not call this confidently without opening the schema and guessing.

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 only 25% across 8 parameters, so the description must compensate; it partly does by mapping 'renames' to name, 'moves' to position, and 'notes' to the warmup/cooldown note fields. But status (an enum) and estimated_minutes get no meaning from either source, and positional/move semantics remain unstated.

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 uses concrete verbs (renames, moves, changes notes) against a specific resource (a training day), which distinguishes it from siblings like add_program_day or update_program_week. However, the enumeration is incomplete — it omits status changes and estimated_minutes, understating what the tool actually does.

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?

No when-to-use context, no prerequisites, and no alternatives (e.g. update_program_week vs. this tool, or add_exercise_to_program_day for contents rather than metadata). The only pointer — 'Day id from get_program' — lives in the schema, not the description.

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