session_mode_set

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

Annotations only declare readOnlyHint=false, so the description adds real value by disclosing the destructive side effect: switching to NATIVE cancels active Workers for this session. It doesn't mention reversibility beyond that or permission requirements, but the key state-change consequence is surfaced.

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 tight sentences, front-loaded with the action and immediately followed by the important side effect. No filler.

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-enum-param mutation with no output schema, the description covers the action, the values, and the notable side effect. Missing only permission/prerequisite context, which is minor 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?

Schema description coverage is 0%, but the single parameter is an enum with values explicitly named in the description text (NATIVE/WORKER). That compensates reasonably, though it adds no meaning beyond the enum values themselves. Baseline for a 1-param tool.

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?

Specific verb (Set) + resource (session mode) + enumerated values (NATIVE/WORKER), and it pairs naturally against sibling session_mode_get as setter vs getter. An agent can tell exactly what this does.

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 operation is per-session and that switching to NATIVE has a side effect, but gives no explicit when-to-use guidance or when to prefer WORKER vs NATIVE. Usage is left to inference.

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