Full user info

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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds real value beyond them: it defines the field scope ('all non-secret fields') and explains why a field may be absent (phone numbers only appear when the other party's privacy settings share them), which prevents misreading a missing value as an error.

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, front-loaded with what is returned, then the default-vs-explicit parameter behavior, then the privacy caveat. No filler and nothing buried.

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 single-parameter read tool with no output schema, the description covers what is returned, the default target, and the main data-availability caveat. The remaining gap is the identifier format for 'user', which an agent needs in order to call it correctly on a non-default account.

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% for the single 'user' parameter, so the description carries the burden. It adds the important default behavior (authorized account when omitted) but never specifies the accepted identifier format (username, ID, phone), leaving ambiguity given the sibling telegram_search_users.

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+resource: it returns the complete User object for one account, and clarifies scope ('all non-secret fields Telegram exposes'). It distinguishes itself from the default-account behavior of telegram_me by noting the authorized account is the default and another user can be targeted, though it never names telegram_me directly.

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 a conditional for the parameter ('pass user to look at somebody else') but never states when to prefer this over telegram_me, telegram_search_users, or telegram_get_contacts, all of which plausibly return overlapping user data. Usage is implied rather than routed.

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