design_set_type

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

With no annotations, the description carries the full burden and does so: it discloses that the operation deletes the entire feature history and parameters, that this is irreversible with no rollback, the exact guard parameter and its failure mode, and the returned fields ('changed', 'history_discarded'). This is exactly the destructive-operation context an agent needs.

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?

Front-loads the destructive consequence in the first paragraph, then preconditions, then return values, then a one-line example. Capitalized warnings and arrow notation make the two directions scannable, and no sentence is 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 two-parameter, no-annotation, no-output-schema tool, everything an agent needs is present: mode semantics, destructive side effects, guard requirement, error outcome, no-op case, return fields, and a usage example.

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%, so the baseline is 3; the description earns an extra point by explaining the consequence behind confirm_discard_history (what is actually discarded and that the user must agree) and by framing design_type as a mode switch rather than a plain enum. Some of the flag's wording overlaps the schema description, keeping it from a 5.

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 and resource: 'Switch the active design between parametric (timeline) and direct modelling,' with both enum states named. This clearly distinguishes it from read-only siblings like design_get_settings and from design_set_units, which changes unit preferences rather than modelling mode.

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?

Explicitly covers each direction (parametric -> direct, direct -> parametric, and same-type no-op), states the precondition (confirm_discard_history=true), instructs the agent to ask the user first, and names the failure behavior (INVALID_PARAMS, nothing changes). No inference is required.

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