check_session

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

Given the annotations already declare readOnlyHint, openWorldHint, and idempotentHint, the description still adds meaningful behavioral context: it excludes api_hash and cookies, notes that stars cabinets are reported but not used, and explains the auth-error recovery path. This goes beyond what annotations convey.

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 compact and front-loaded with the core action. Each sentence adds distinct value: what it does, what it returns, what it does not return, and how to recover from auth failure. There is no filler 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 zero-parameter, read-only session check with an output schema, the description is complete. It covers expected return fields, important exclusions, and failure handling. An agent has everything needed to decide when to call it and what to do with the result.

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 input schema has zero parameters, so there are no parameter semantics to document. The baseline for a no-parameter tool is 4, and the description correctly focuses on behavior and return data instead of inventing parameter guidance.

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 starts with a specific verb and resource: 'Ping the current ads.telegram.org session.' It clearly distinguishes check_session from siblings like reload_session and get_account by focusing on checking session state and returning ownership/cabinet/balance information. The purpose 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 description gives an explicit conditional usage path: if ok=false with code=auth, tell the user to refresh cookies and call reload_session. This directly references an alternative tool and the condition that triggers it. It does not broadly compare against all sibling tools, but provides sufficient situational guidance for the main failure case.

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