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

Beyond the readOnlyHint and openWorldHint annotations, it discloses exact-count fallback behavior, rounded media counters, public-web-preview/no-login access, exclusion of private and user accounts, old-username takeover semantics, and the 1-credit cost. This is rich behavioral context that materially helps correct invocation.

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 purpose is front-loaded in the first sentence, followed by tightly relevant caveats about exact counts, rounded counters, access limitations, handle behavior, and cost. Despite being longer than a minimal definition, every sentence adds actionable context and there is little waste.

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?

With no output schema, the description does the necessary work by enumerating the returned metadata fields and explaining count reliability and counter rounding. It also covers access limitations, handle caveats, and cost, leaving only the optional cache_max_age parameter unexplained.

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 already explains the handle formats, but the description adds important semantic nuance: an old username resolves to the channel that took it over, and the handle may differ from the one embedded in a post id. It does not describe cache_max_age, which is undocumented in the schema as well, so the 50% schema coverage is only partially compensated.

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 identifies the resource and the returned metadata: public Telegram channel or group metadata, including name, description, avatar, verification, subscriber count, and media counters. It does not explicitly name the sibling telegram_channelPosts as the alternative for posts, so sibling differentiation is implied rather than explicit.

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?

It gives clear coverage boundaries: public web preview only, no logged-in account, and private channels, invite-only groups, and user accounts are not covered. It also warns to join on a post id rather than the handle. However, it does not explicitly direct the agent to telegram_channelPosts for posts or another sibling for related data.

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