end_session

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

With no annotations provided, the description carries the full burden and does most of the work. It discloses parsing behavior for duration, optional title, unit selection, and the return format including text, PNG images, and multi-page output for long workouts. It stops short of noting edge cases like calling end_session with no open workout.

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 description is compact and front-loaded: 'End the open workout.' appears first, followed by efficient parameter details and return behavior. Every sentence contributes meaningful information without redundancy.

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?

The description covers the core action, parameter behavior for three of four parameters, and the return value despite lacking an output schema. It is slightly incomplete because theme is undocumented and there is no guidance about preconditions or alternative tools, but it provides enough for a capable agent to invoke the tool correctly in most cases.

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 0%, so the description must compensate. It explains duration with concrete examples, clarifies that title is optional, and specifies unit values (kg or lb) and their effect on totals. However, the theme parameter is not mentioned at all, leaving one of four parameters semantically unexplained.

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 uses a specific verb and resource: 'End the open workout.' It clearly identifies the operation and distinguishes it from sibling tools like session_card and log_set by focusing on ending the session. It also states the return artifact, which reinforces the tool's role.

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?

The description implies the tool is used when a workout is finished, but it provides no explicit when-to-use guidance or alternatives. It does not mention conditions like needing an open workout first, or when a sibling tool such as session_card should be used instead.

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