get_contacts

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

With no annotations, the description carries the behavioral disclosure burden. It communicates that the operation is a read-only listing of the account's contacts, which implies no destructive side effects. It does not mention authentication, data freshness, or potential errors, but those are secondary for such a straightforward getter.

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 one short sentence with no filler, and the core meaning is front-loaded. It adds the useful clarifying context 'Telegram address book' without redundancy.

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 parameterless read-only tool with an output schema available, the description is largely complete: it states what is returned and whose data it returns. It could add an explicit statement about requiring an authenticated account, but that is inferable from 'account contacts.'

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 tool has zero parameters, so the input schema fully specifies the interface (100% coverage vacuously). Per the baseline for 0-parameter tools, the description needs to add no parameter detail, and the 4 is appropriate.

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 identifies the resource as the account's contacts/Telegram address book, which clearly distinguishes it from sibling tools like get_chat or get_participants. However, it is phrased as a noun phrase rather than an explicit verb+resource statement, and it doesn't directly name alternatives.

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?

Usage context is implied by the name and description: call this when the account's contact/address book list is needed. There is no explicit guidance about when not to use it or which alternative to prefer, but the tool is simple enough that this is a minor gap.

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