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

Beyond the annotations (readOnly, idempotent, non-destructive), the description discloses two non-obvious traits: the tool performs no action in the portal itself ('opens nothing by itself') and the actual execution must happen through the cotlet_browser_* tools. That is meaningful context an agent could not infer from the readOnlyHint alone. It does not describe the exact shape of the returned guidance beyond 'screens, buttons, fields'.

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?

The content is dense but not front-loaded: the decisive fact that this tool only returns instructions appears after the misleading 'List pt sessions' opener, and the trailing 'CoachingPortal's official API: CoachingPortal publishes no public API' is redundant phrasing that repeats the tool name awkwardly. Semicolon-chained clauses make the flow harder to parse than it needs to be.

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?

With no output schema, the description carries the burden of explaining what comes back, and it does so at a high level (step-by-step screens, buttons, fields) plus the handoff to browser tools. It is close to complete for a zero-parameter, read-only guidance tool, with only the exact return format left vague.

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 tool takes zero parameters and the schema has full coverage, so there is nothing for the description to disambiguate; the 0-param baseline applies. The description correctly implies no inputs are needed to retrieve the instructions.

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 resource (pt sessions) and scope (the user's own account), and it does disclose the critical twist that it returns step-by-step instructions rather than data. However, the headline verb 'List' directly conflicts with 'returns how to do it... and opens nothing by itself', so an agent skimming the first clause will mispredict the return value. The true behavior is stated, but it is not stated first, leaving the tool's purpose ambiguous at a glance.

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?

It gives a clear follow-on path: use this for the how-to, then execute with the cotlet_browser_* tools in the CoachingPortal Cloud Browser. It also explains why this path exists (CoachingPortal publishes no public API). It stops short of saying when to prefer this over the sibling mutation tools such as coachingportal_manage_pt_session, but the core usage context is explicit.

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