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

Beyond the annotations (destructiveHint, idempotentHint, readOnlyHint), it discloses propagation timing ("Installed widgets pick the change up on their next page load"), a plan-gating constraint ("hiding [branding] needs a plan that allows it"), and the brand_color/action_color inheritance rule. It does not cover auth scopes or rate limits, but adds substantive behavioral context.

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 key contract and prerequisite are front-loaded, and the long field enumeration is justified by 13 parameters. It is dense but each clause maps to real parameters or behavior, with little waste.

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 13-parameter mutation tool with no output schema, the description covers what changes, what persists, when changes take effect, and plan gating — enough for correct invocation. Minor gaps (auth requirements, per-field validation beyond enums) remain.

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 only 15%, so the description must compensate, and it largely does — enumerating colours, theme, header style, start screen, greetings/launcher text per language, launcher icon/side/offsets, deflection, and branding. The action_color vs brand_color interaction is explained, though a couple of flags (e.g. launcher_pulse) rely on the schema.

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 opens with a specific verb and resource — "Set how a website inbox's chat widget looks and behaves" — and then enumerates the concrete aspects (colours, theme, header style, start screen, greetings, launcher text/icon/offsets, deflection mode, branding). This clearly distinguishes it from siblings like update_inbox, so an agent can route 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?

It states the partial-update contract ("Only the fields you pass change") and a prerequisite ("read get_inbox first"), plus an advisory ("say so when changing [action_color]"). Clear context for use, though it names no explicit when-not condition or alternative tool.

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