timeline_set_model_parameter

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 well: it discloses the atomic failure semantics (old expression restored, call fails with the feature's message, details.reverted=true) and the allow_errors override. It does not say whether the document must be active or whether downstream features rebuild, which keeps it off a 5.

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?

The purpose is front-loaded in the first sentence, failure behavior follows, then return shape and an example. No sentence is redundant.

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?

There is no output schema, so the description supplies the return shape itself, along with the error/revert contract and the sibling routing. Nothing needed to call it correctly is missing.

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 adds a concrete call example (name="d3", value=30 -> "30 mm") that clarifies the units/value interaction beyond the field descriptions. It does not, however, add anything about allow_errors that the schema does not already state.

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 precise verb ('Set') and a scoped resource ('expression of a model parameter, one created by a feature') and names the sibling that handles the other parameter class. An agent can distinguish it from parameter_update without opening the schema.

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 routes user parameters to parameter_update, which is the key selection decision among the parameter_* siblings. It also specifies the when-not case for the error-state path via allow_errors.

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