Resolve a Telegram username

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

Annotations already declare readOnlyHint=true, and the description adds that it can resolve users, channels, and chats. It does not clarify behavior for non-existent usernames, whether the entity type is returned, or any rate limits. The description adds some context but not rich behavioral detail.

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, focused sentence that front-loads the key action and resource. No unnecessary words or repetition.

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 lookup tool with read-only annotations and no output schema, the description covers the essential purpose and input. It lacks details about return value or error handling, but for a resolution tool this is a minor gap given the clear input and purpose.

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?

The schema describes the 'username' parameter (with or without @), but the 'accountId' parameter has no description in the schema. The tool description does not mention accountId at all, leaving its purpose and usage unclear. With 50% schema coverage, the description should compensate for the undocumented parameter but does not.

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 clearly states the action ('look up') and the resource ('user, channel, or chat') with a specific input mechanism ('by @username'). This distinguishes it from sibling tools like get_user_info or check_username, which have different scopes or 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 description implies when to use the tool: when you have a @username and need to resolve it to an entity. However, it does not explicitly mention when not to use it or suggest alternatives, such as using search_global for broader lookup or get_user_info if an ID is already known.

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