getChatMemberCount

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

No annotations are provided, so the description carries the burden. It conveys a read-only 'Get' operation and states the successful return type, but does not discuss error cases, permission requirements, or any caveats such as approximate counts. This is adequate for a simple read operation but not richly transparent.

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 concise sentence with a second short sentence for return type. It contains no filler and front-loads the primary purpose. Every word 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 tool with one required parameter and no output schema, the description is nearly complete: it names the resource, the operation, and the return type. Minor omissions such as failure behavior and edge cases prevent a 5, but the essential information for correct invocation is present.

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?

There is only one parameter and the schema description covers 100% of it, clearly defining chat_id as either an integer ID or a @username. The description adds no further parameter-specific meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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 a specific action ('Get the number of members') and resource ('a chat'), plus the return type ('Returns Int on success'). This clearly distinguishes it from sibling tools like getChat, getChatMember, and getChatAdministrators, which serve different purposes.

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 intended use is implied: use this when you need a chat's member count rather than member details or chat metadata. However, it does not explicitly name alternatives or provide when-to-use/when-not-to-use guidance, so the agent must infer the selection context.

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