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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds only that the response includes the chats in the list, plus the “custom” qualifier; it says nothing about behavior when both id and name are supplied or about missing/ambiguous lists.

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?

A single front-loaded sentence with no filler; the scope and lookup keys are stated immediately.

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 simple read tool with full schema coverage, an output schema, and complete annotations, only minor gaps remain (ID-vs-name precedence, pointer to list_chat_lists for discovery). Nothing essential to a correct call 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?

With 100% schema description coverage, the baseline is 3. The description's “by ID or name” restates what the schema already documents and gives no precedence rule or guidance for the optional target_session routing parameter.

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 (Get) and resource (one custom chat list plus its chats), and the singular “one” implicitly separates it from list_chat_lists. It does not explicitly name the sibling, but the scope is unambiguous.

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?

The phrase “by ID or name” hints at two invocation paths, and “one” implies the difference from a list operation, but there is no explicit when-to-use guidance and no mention of list_chat_lists as the way to discover IDs (that hint exists only in the schema).

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