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

Annotations already declare readOnly/idempotent, and the description adds genuinely new behavior: reading never creates a chat, a missing chat yields exists=false with defaults and no snippet, and the first update/set_placement is what creates it. It also discloses a permission constraint — allowed domains and widget key are only editable by a person in the Ignix UI — which is invisible in the schema.

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-loaded with the resource and its returned fields, then the usage routing, then the existence edge case — a sensible order. The field enumeration and the closing UI-permission sentence are long but each carries actionable information, so little is wasted.

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?

With no output schema, the description compensates by enumerating the returned fields, the placement sub-fields, allowedDomains, the snippet, and the exists flag. It also covers the not-yet-created edge case and the permissions boundary, leaving nothing an agent needs before calling it.

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?

Only one optional parameter and schema coverage is 100%, so the schema already fully documents workspaceId (including its default). The description's 'Each workspace has one chat' hints at the cardinality behind the parameter but adds no syntax or format detail beyond the schema, so the 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 and resource ('Read the web chat bubble the customer embeds') and enumerates exactly what is returned (title, greeting, colours, placement, allowedDomains, snippet). It also distinguishes itself from siblings by naming update_web_chat and set_web_chat_placement as the mutating counterparts.

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 prescribes 'Use it before changing anything' and routes each alternative to its own scope: update_web_chat changes what visitors see, set_web_chat_placement only moves or hides the bubble. This is an explicit when-to-use plus when-to-use-something-else.

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