end_session

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

Annotations already indicate readOnlyHint=false, so the description's 'Mutating session operation' is consistent. It adds value by explicitly stating what the operation does NOT do: 'It does not mark the project complete or commit a draft.' This clarifies side effects beyond the annotation metadata.

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 concise and front-loaded with its mutating nature, followed by a concrete action and clarifying non-effects. 'Safely through the engine' is slightly vague but does not undermine clarity.

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 zero-parameter mutating operation with output schema and annotations provided, the description is largely complete. It explains the core action and important non-effects. It does not mention whether the session can be resumed later, but this is not essential for basic invocation.

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 has zero parameters and the schema coverage is effectively 100%, so there is no parameter documentation burden. The description appropriately focuses on behavior rather than inputs.

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 clearly states the operation: 'End the active Design Flow session safely through the engine.' It identifies a specific verb and resource, and clarifies it is a mutating session operation. It does not explicitly distinguish itself from sibling tools, but the purpose is unmistakable.

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 use when ending an active Design Flow session, but it gives no explicit guidance on when to use this tool versus alternatives like resume_project, new_project, or lock_round. There is no scenario-based direction or exclusion criteria.

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