set_privacy

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

The annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=true, so the safety profile is partly covered. The description usefully adds that per-user exceptions are preserved (a side effect not derivable from the annotations), but it says nothing about the dry_run parameter that defaults to true, which is central to how a caller should behave before committing a change.

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?

Two short sentences with the core action front-loaded and the advisory second. The trailing rationale ("so strangers cannot add you to spam groups") is slightly verbose but earns its place by justifying the recommendation.

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?

This is a mutation tool with no output schema and zero schema description coverage, yet the description omits the dry_run default, the scope of a single-setting change, and any confirmation or reversibility guidance. An agent could call it correctly only by guessing at the schema defaults.

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 0%, so the description carries the full burden and only partially delivers. It hints at the `setting` enum via the group_invites/contacts example and thereby implies the `level` values, but `dry_run` — the parameter most likely to be misused — is never mentioned and no parameter meaning is explained.

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 specific verb and resource ("Change one privacy setting") and scopes it to a single setting, which cleanly distinguishes it from the read-only sibling get_privacy. It stops short of naming any sibling explicitly, so it lands at 4 rather than 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?

It offers a concrete recommendation (group_invites=contacts to block strangers from spam groups), which implies a use case, but never says when to call this versus get_privacy first, nor anything about when not to change a setting. Usage is suggested rather than prescribed.

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