Channels Telegram considers similar

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

Annotations already indicate readOnlyHint and openWorldHint, so the safety profile is covered. The description adds useful behavioral context beyond annotations: results are based on shared audience rather than vocabulary, and result counts vary ('Large channels return roughly a dozen; small or very new ones return none'), which sets accurate expectations.

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 three focused sentences with no fluff. It front-loads the core action and differentiator, then adds a practical usage note and a caveat about result size. Every sentence 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, full schema coverage, and safety annotations, the description covers the essential conceptual model, typical use case, and result-size expectations. There is no output schema, but the format parameter in the input schema documents output shapes, so the missing return-structure detail is not a significant gap.

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%, so the baseline is 3. The description does not add new parameter-level guidance beyond the schema; the only relevant nuance is that 'a given channel' maps to the channel parameter, but this is already apparent from the schema and context.

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?

Description uses a specific verb ('Return') and resource ('channels Telegram itself recommends alongside a given channel'), and clearly differentiates itself from keyword search by stating it is Telegram's 'own topical judgement, not a keyword match.' This makes the purpose unmistakable and distinct from its siblings.

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 explicit usage context: it is 'the way to discover channels whose names you do not already know' by starting from a known channel and walking outward. It also implies when not to use it (when you need keyword-based discovery), though it does not explicitly name sibling alternatives like telegram_search_channels.

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