telegram_contacts

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

With no annotations at all, the description carries the full burden and does a good job on safety: it declares 'Read only' (substituting for readOnlyHint) and discloses a non-obvious projection rule that phone numbers are never returned, only a phone_number_present fact. Gaps remain on pagination, result caps, and error behavior.

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?

Three short sentences, zero filler, with the resource and the privacy guarantee front-loaded. Nothing is repeated from the schema or title.

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?

There is no output schema and no annotations, so the description is the only behavioral source; it covers the safety/read-only profile well but leaves the return shape, pagination behavior, and query matching semantics undocumented. Adequate but with real gaps for an agent that must construct correct calls.

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 0%, so the description must compensate for all three parameters and does not: it never states what 'query' matches (display name, username, phone?), nor that 'limit' caps at 100, nor that 'query' is required or ignored when mode=list. Only the mode split is loosely implied.

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 gives a specific verb pair (lists or searches) and a specific resource (known Telegram user contacts), which is clearly distinguishable from message- and chat-oriented siblings. It does not explicitly name the closest ambiguous alternative, telegram_public_search, so the boundary between 'known contacts' and 'public search' is left implicit.

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?

'Lists or searches' implies the two modes and thus when to use each, and 'known ... contacts' hints that this is scoped to the account's own contact graph rather than public users. However, there is no explicit statement of when to prefer this over telegram_public_search or telegram_inbox, and no mention of prerequisites or exclusions.

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