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

Annotations only declare readOnlyHint=true; the description goes beyond that by disclosing conditional behavior — the Slack portion appears only 'when the account has connected Slack' and the Google Chat portion only when that is connected. It also reveals the identifier formats (slack:T…:U…, gchat:<org>:users/…) an agent will have to handle. Missing are any notes on result sizing, empty-state behavior, or ordering.

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 content is dense and every clause carries information, but it is delivered as a single semicolon-and-em-dash run-on sentence with no lead-in clause or bullet structure. A short front-loaded sentence ('Lists everyone this Agent can send requests to') followed by the source categories would have made it far easier to scan.

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 one-parameter read tool with no output schema and only a readOnlyHint, the description does the heavy lifting well by naming each returned category and the ID field each carries. The main omission is that required parameter semantics live entirely in the schema, and nothing is said about what happens when no integrations are connected.

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?

There is exactly one parameter and schema description coverage is 100%; the schema already explains that agent_id comes from list_agents or create_agent. The description says nothing about agent_id at all, so it adds no meaning beyond the schema. The high-coverage baseline of 3 applies.

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 enumerates precisely what is listed — paired people by email/Profile, pending email invitations, Slack members and app channels with slack_id, and Google Chat users with gchat_id. That is far more specific than the title 'List Recipients' and it implicitly positions itself as the lookup feeding send_request. It stops short of a clean verb-first statement and never directly contrasts itself with sibling listers, so it is clear but not maximally distinguishable.

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 is only implied: the repeated 'for send_request' tags signal that these identifiers exist to be passed to send_request, which suggests calling this first. There is no explicit when-to-use, no when-not-to-use, and no comparison against alternatives such as list_agents. Context is inferable but not stated.

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