set_session_mode

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

No annotations provided, so description carries full burden. It discloses that mode becomes immutable once set, which is critical behavioral info. Missing details on failure behavior or permissions, but for a simple tool with output schema, it's adequate.

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 sentences, front-loaded with purpose and condition. No wasted words. Efficiently communicates the essential behavior.

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?

Given low complexity (2 params, no nested objects, output schema exists), the description covers core behavior and condition. Minor gaps: does not explicitly state that the session must exist or describe the output/errors, but output schema likely fills that gap.

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%, but the description adds nothing about parameters. While the schema provides enum values for mode, the description does not explain parameter roles or usage beyond the generic 'set a session's mode'.

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 tool sets a session's mode and adds a key condition (only succeeds if no mode set, then immutable). This distinguishes it from other session tools like clear_session or start_session.

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 provides a clear precondition ('Only succeeds if no mode is set yet'), guiding the agent on when to call. However, it does not explicitly mention when not to use it or list alternative tools for related operations.

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