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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is fully covered. The description adds value beyond that by disclosing the shape of what is read (slots, targets, allowed exercises, logged sets), though it says nothing about size limits or how much history is included.

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, each doing distinct work: trigger, return contents, and exclusion/alternative. Front-loaded with the use case and no redundant restatement of the name or title.

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 single-parameter read tool with a full output schema and rich read-only annotations, the description covers everything an agent needs to decide to call it and where to source the id. Return-value explanation is a bonus rather than a necessity here.

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?

The schema provides zero description coverage for sessionId, but the description compensates by explaining that the id comes from get_today or get_schedule and that it selects a single session 'in full'. Format details (opaque string vs. structured id) are still unstated, keeping it below a 5.

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 ('need one session in full, by its id') and immediately enumerates what is returned — slots with targets, slot-allowed exercises, and logged sets. This is clearly distinguishable from the sibling list/detail tools.

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 when-to-use trigger ('when you need one session in full'), names where the required id comes from (get_today or get_schedule), and states an explicit exclusion plus the alternative ('Do not use to list sessions; use get_schedule').

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