get_chat_member_count

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

No annotations are provided, so the description carries full burden for behavioral disclosure. The description is pure tautology of the name and gives no behavioral context such as return format, whether the count reflects current membership or cached value, authentication requirements, or rate-limiting considerations. The tool reads like a simple lookup but offers no information beyond what the name already states.

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 description is a single efficient sentence with zero waste. It's appropriately terse for a simple tool. Being slightly too minimal rather than verbose is offset by its clarity, though it could arguably benefit from one or two more useful details.

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?

The context signals show a simple tool: 1 parameter, 100% schema coverage, an output schema exists, no nested objects, and no annotations. With an output schema present, the description needn't explain return values. However, for a tool that counts members, some usage context (which chat types are supported, bot membership requirements) would improve completeness. Given its simplicity, it's adequate but leaves the agent guessing on edge cases.

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%, with the single chat_id parameter fully documented as 'Unique identifier for the target chat or username.' The description itself adds no parameter details beyond what the schema already provides, so the baseline of 3 applies. No additional semantic guidance like accepted formats for numbers vs usernames is added.

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 'Return the number of members in a chat' uses a specific verb (Return) with a clear resource (member count in a chat). It distinguishes from siblings well since none of the sibling tools (get_chat, send_message, etc.) are about member counts, making the purpose 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?

There is no guidance on when to use this tool versus alternatives. It doesn't mention whether this works for all chat types (private, group, supergroup, channel), any prerequisites (e.g., bot must be a member), or when one might prefer get_chat instead. No exclusions or context are provided.

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