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

Annotations already declare this is a non-read-only, non-destructive write. The description adds real value beyond them by disclosing the downstream effect (load_au = sRPE × duration_min, Foster method) and that the data feeds the same load currency as TSS. It does not state whether re-logging overwrites an existing sRPE or what the response contains.

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 core action and scale definition, then the derived-metric consequence. Dense but every clause carries information; mild jargon stacking (sRPE, load_au, TSS) is offset by the parenthetical explanations.

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 2-parameter mutation with no output schema, the description covers scale, timing, prerequisite, and the computed side effect, which is what an agent needs to call it correctly. Missing only the overwrite/duplicate behavior and return-value expectations.

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 0%, so the description must compensate, and it largely does: it pins srpe to the app's 1-10 scale, identifies it as Foster's session-RPE, and specifies the ~30 min post-session timing. It also clarifies that activity_id must reference a completed activity from list_activities. Exact ID format is still unspecified.

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 and resource ('Attach the athlete's session RPE ... to a completed activity') and names the upstream tool (list_activities) that supplies activity_id. It does not explicitly differentiate from the near-sibling log_rpe_marks, so it stops short of full disambiguation.

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 clear when-to-use context: ~30 minutes post-session, applies to any sport including gym/tennis where no power meter exists. The prerequisite of a completed activity is stated. There is no explicit exclusion telling the agent when to prefer a different sibling tool.

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