iam_friend_policy

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

With no annotations, the description carries the burden and does substantial work: it warns the tool cannot enable owner permission or accept a friendship, notes external messages are non-owner content, flags that owner risk review is Desktop-only, and states stale choices are invalidated by policy changes. These are meaningful behavioral constraints, though some phrasing is terse.

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?

Purpose is front-loaded and the constraints follow in order. It is dense but each sentence carries a distinct rule; the ALL-CAPS clauses are slightly noisy but not wasteful.

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 3-param, no-annotation tool with an output schema, the description covers safety constraints, write preconditions, and revision semantics well. The main gap is the undocumented mailbox parameter, which keeps it short of 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 coverage is 0%, so the description must compensate. It meaningfully explains opted_in (only when owner allows) and revision (use the returned revision), but says nothing about the mailbox parameter, leaving one of three params unexplained.

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 and resource: 'Inspect your external-contact permission.' A reader understands it reads (and optionally sets) the friend/external-contact policy. It doesn't explicitly differentiate from the sibling iam_friend, so it stops short of a 5.

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 clear conditional for the write path: 'Choose opted_in only when your owner has explicitly allowed agent choice, using the returned revision.' This tells the agent when to set versus just inspect. It does not name sibling alternatives like iam_friend, which keeps it below 5.

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