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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description complements these by explaining what the tool returns (contacts plus template) and the downstream relationship to create_referral_invites. It doesn't disclose the invite template's content or pagination behavior, but given the annotation coverage this is reasonable.

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 sentences, no filler, front-loaded with the core purpose. Every sentence earns its place: what it returns, when to use it, and how it relates to the sibling tool create_referral_invites. Zero waste.

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?

The tool is a simple read-oriented listing operation with an output schema and only one optional parameter. The description covers the purpose, return content (contacts + template), and downstream tool coupling. Adequate for this complexity level; slightly lacking detail on the invite template format but the output schema likely covers that.

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 coverage is 100% — the single 'limit' parameter is fully described as 'Max contacts to return (default 60)', which is complete. The description adds the default context implicitly but doesn't go beyond the schema. Baseline 3 applies when the schema fully documents the parameter.

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 clearly states what the tool does: 'Returns the user's emailable contacts plus an invite template, for recommending LMCP to a colleague.' It names the specific verb (list/returns), the resource (referral candidates), and the purpose (recommend to colleague). It distinguishes itself from create_referral_invites by explicitly noting the division of labor.

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 explains when a user would invoke this ('when they want to invite or recommend someone') and situates it in a workflow by mentioning create_referral_invites generates invite links afterward. It lacks explicit 'when-not-to-use' or named alternatives, but within this tool set the purpose is clear enough to discriminate use.

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