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

The description discloses a real behavioral trait the annotations don't capture: the call is confirm-gated and returns only a preview until confirm: true is set. That is exactly the kind of write-safety context an agent needs. It stops short of saying what happens after execution (duplicate detection, whether the entry can be edited/removed) — delete_client_workout_log exists, but the description doesn't say this tool is reversible.

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 compact sentences with the core action front-loaded and the gating behavior appended in parentheses. The "per-set reps and weight (kg)" clause is largely restating the schema, but the total length is well within budget and easy to scan.

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 nested-object mutation with no output schema and 50% parameter coverage, the definition covers the confirm gate but says nothing about the return payload shape (preview object vs created log), how plan/source/compliance fields interact, or what the preview contains. Minimum viable rather than complete.

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?

With 50% schema coverage on a nested object, the description only addresses the inline set data (reps, weight in kg) and the confirm gate. It adds no meaning for rpe, rir, restSeconds, source, compliance, planId, durationSeconds, notes, or which fields are required versus optional. Adequate but not compensating for the coverage gap.

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 names a specific verb and resource ("Log an exercise for a client") plus the per-set reps/weight data it accepts, so the agent knows it creates a workout log entry rather than a diet or habit log. It does not name or differentiate against near siblings like get_client_workout_logs or delete_client_workout_log, so it falls 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?

"On their behalf" implies the coach-side/PT logging context, and the confirm-gate note tells the agent it will get a preview first. However, there is no explicit guidance on when to prefer this over read siblings or how it differs from other log_* tools, leaving the choice to inference.

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