list_contacts

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

The description explicitly states 'Read-only', which is a useful behavioral disclosure. However, with no annotations provided, the description carries the full burden, and it does not disclose other behavioral traits such as pagination behavior, whether the query filter matches partial strings, or how the limit cap of 500 behaves. The read-only note adds value but leaves gaps.

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 two short sentences with no wasted words. The core purpose is front-loaded, and the read-only note is placed efficiently. Every word earns its place.

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 simple read-only list tool with two optional parameters and full schema coverage, the description is mostly adequate. However, it lacks any mention of return format or pagination behavior, and with no annotations or output schema, a bit more context about what the response contains would make it complete.

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 100%, so the schema already documents both parameters. The description adds the phrase 'optionally filtered by name', which aligns with the query parameter but does not add meaning beyond the schema's 'Case-insensitive filter over name and @username'. Baseline 3 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 states a clear verb-resource pair: 'list' the account's 'saved contacts', and adds the optional name filter. It is distinguishable from siblings like list_chats and list_members because it targets saved contacts, though it does not explicitly name a sibling to differentiate from.

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?

The description implies usage context: it is a read-only listing of saved contacts with an optional filter. It does not explicitly state when to use this over alternatives like list_chats or search_public_chats, nor does it provide exclusions, so guidance is only implied.

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