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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false and idempotentHint=false, so the safety profile is covered. The description adds genuinely useful PATCH semantics beyond the annotations, but says nothing about what happens to the undocumented 'additionalProperties' settings, error behavior on an unknown id, or permission requirements.

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 terse sentences with zero waste; the core operation is front-loaded and the patch caveat follows immediately. Nothing to trim.

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 mutation tool with a nested, open additionalProperties object and only two sentences of prose, the definition is adequate but thin: it does not mention the external docs link that the schema references, nor whether additional settings are merged or replaced. Annotations cover mutability, but the interaction with the extensible 'data' object is left unexplained.

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 coverage is 100% and the nested 'data' object documents name, persona_id, scenario_id and assistant_id, so the schema carries the parameter burden. The description only says 'selected simulation fields' without naming any of them, adding no meaning beyond the schema — baseline 3 applies.

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?

States a specific verb ('Update') and resource ('simulation fields') plus the key patch semantic that omitted fields retain their values. The resource is clearly distinguishable from the persona/scenario/run siblings by name, though the description never explicitly contrasts with them.

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?

'Omitted fields retain their values' implicitly tells the agent this is a partial update and that only changed fields need to be sent. However there is no explicit when-to-use vs. create_simulation or update_simulation_persona/scenario, and no mention of prerequisites such as the simulation existing or being in an editable state.

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