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

Annotations already declare destructive=true and idempotent=true, but the description adds two traits they cannot convey: changes 'go live on the website at once' and the update is partial, touching only passed fields. It also discloses what the tool cannot do (allowed domains, widget key), which is useful boundary information. It does not cover permissions/auth requirements or rate limits.

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?

Three sentences, front-loaded with purpose, then patch semantics, then the live-change warning and exclusion. The long field list in sentence one is somewhat redundant with the schema but functions as a scannable overview, so it mostly earns its place.

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 28-parameter mutation with no output schema, the description covers the critical facts an agent needs: partial update semantics, immediate publication, the confirmation obligation, and what is out of scope. The only real gap is that it says nothing about what the call returns or how failures surface, which matters slightly given no output schema.

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 100% and every one of the 28 parameters is individually documented in the schema, so the description's field enumeration is largely a restatement of structured data. Baseline 3 applies; the narrative grouping ('what visitors see') adds only mild orientation value over the per-field descriptions.

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 names a specific verb and resource ('Change what visitors of the customer's website see in the chat') and enumerates the editable surface (title, greeting, colours, logo, pre-chat form, placement, etc.), so an agent immediately knows this is the full web-chat configuration writer. It does not explicitly differentiate itself from the narrower sibling set_web_chat_placement, which overlaps on the 'placement' field it lists.

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 gives real operating guidance: 'Only the fields you pass change' (patch semantics), 'show the user what will change and confirm first' (a required confirmation step before an immediate live change), and an explicit exclusion ('allowed domains and the widget key can only be changed by a person in the Ignix app'). It stops short of naming alternatives such as reading current state with get_web_chat first.

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