get_pinned_messages

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

Beyond readOnlyHint/openWorldHint it discloses authorization nuances (forum topics need ordinary access; public-channel permission does not authorize forum groups), pagination mechanics (follow next_cursor with the same chat_ref and topic_id, respect retry_after_seconds), and the consistency caveat that pin membership can change during traversal. It also states explicitly that nothing is pinned, unpinned, or marked read, which reinforces rather than contradicts the annotations.

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?

Purpose is front-loaded in the first clause, and each subsequent sentence covers a distinct concern (topic scoping, access policy, pagination/retry, mutation guarantee) with no filler or repetition. The length is justified by the number of real behavioral constraints.

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 read-only traversal tool with no output schema, the description covers ordering, scoping, access prerequisites, cursor recovery, transient-failure handling, and side-effect guarantees — everything an agent needs to call it correctly and to interpret a mid-traversal shift in results.

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?

With 0% schema description coverage the description carries the load, and it does so for chat_ref (ID, @username, t.me link), topic_id (omit = chat-wide, positive = forum topic, General is 1, exclusive-minimum>0 implied), and cursor (must be replayed with the same chat_ref and topic_id). Only 'limit' is left unaddressed beyond its schema default/maximum, which keeps this just below a 5.

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?

States a specific verb and resource ('Read a chat's pinned messages'), order ('newest first'), and accepted reference forms ('by ID, @username or t.me[/s] link'). No sibling tool operates on pinned messages, so the agent can discriminate it from get_messages/get_history/search_messages without opening a schema.

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?

Gives explicit when/when-not guidance for topic_id ('Omit topic_id for chat-wide pins, or supply a positive forum topic ID (General is 1)') plus the access-policy split between forum topics and public-channel pins. It lacks a direct pointer to the alternative sibling (e.g. get_history or search_messages) for non-pinned retrieval, so it stops short of full routing guidance.

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