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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint. The description adds conditional return details: 'forum chats may include topics up to topics_limit; user targets may include common_chats up to common_chats_limit,' which is useful behavioral context not provided by annotations. No contradiction.

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?

Two concise sentences with a doc link. Purpose is front-loaded with no filler, and the documentation link adds optional depth without bloating the description.

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 an output schema present and annotations covering safety, the description covers purpose, success shape, conditional fields, and links to full docs. This is complete for a read-only single-target tool.

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 covers both parameters with descriptions at 100% coverage, so baseline is 3. The description adds only a redundant note about topics_limit's effect and mentions a non-parameter common_chats_limit, providing marginal value beyond 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 states 'Load profile and metadata for one user, bot, group, or channel' – a specific verb and resource, with a clear scope of a single target. It naturally differentiates from siblings like get_messages (messages) and find_chats (search).

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 description makes it clear this tool is for retrieving metadata for a single chat, based on the verb and resource. It does not explicitly name alternatives or exclusions, but the context is unambiguous enough to guide selection.

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