session_set_reasoning

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

Annotations indicate a mutating but non-destructive operation, and the description adds a useful caveat: support is conditional. However, it does not disclose what happens when a provider is unsupported, whether existing reasoning settings are overwritten, or any side effects on the session.

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?

A single sentence that is fully front-loaded with the essential action, target, and limitation. There is no redundant wording or 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 required-parameter mutation tool with no output schema, the description leaves key operational questions unanswered: which providers support reasoning changes, what input values effort accepts, and how unsupported cases behave. The presence of sibling tools like set_reasoning makes this incompleteness more costly.

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?

With 0% schema description coverage, the description must compensate, but it only partially maps to parameters: 'reasoning effort' hints at effort and 'exact native session' hints at nativeId. The required provider parameter is entirely unaddressed, and valid effort values are not explained.

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 ('Change') with a clear resource ('reasoning effort') and a distinct scope ('an exact native session'). It also signals a capability boundary with 'when supported,' which helps distinguish it from broader tools like set_reasoning or session_set_model.

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 no guidance on when to prefer this tool over siblings such as set_reasoning, session_set_model, or other session-related tools. 'When supported' hints at conditional applicability but gives no criteria, alternatives, or exclusions.

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