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

Annotations already declare idempotentHint=true and destructiveHint=false, so the description's main added value is the undisclosed operational context: it requires a connected account with training:write plus a membership that already includes programs, and it fails loudly with no side effect otherwise. It also confirms no purchase flow is triggered, which no annotation conveys.

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?

Front-loaded with the precondition sentence and each sentence carries distinct information. Minor redundancy: the retry/idempotency sentence restates both idempotentHint and the schema's own description of idempotency_key, and the link-sharing instruction is stated twice in effect.

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 not be explained, yet the description usefully notes a link is returned and to share it. Combined with permission requirements, failure behavior, and idempotency, an agent has everything needed to invoke this mutation correctly.

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 three parameters are already documented in the schema, including the idempotency_key reuse rule. The description only reinforces the retry semantics rather than adding new parameter meaning. Baseline 3 is appropriate.

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 (saves a previewed program to the connected Phorme account as a private program) and names the sibling it depends on, preview_program_import. An agent can distinguish it from preview_program_import and save_workout_to_phorme without opening any schema.

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?

Gives an explicit gating condition ('only after preview_program_import returned a preview and the user clearly said to save it') and an explicit exclusion ('It never starts a purchase'). The alternative path is named, so the when/when-not is fully determined.

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