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

Annotations declare destructiveHint=true, readOnlyHint=false, and openWorldHint=false, so the safety profile is already carried by structured fields. The description adds nothing beyond that: it doesn't say whether this revokes existing access, whether omitted flags are left untouched or cleared (critical, since all four parameters are optional), or whether a confirmation step is required.

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?

A single front-loaded sentence with no filler or repetition. It is efficient, though the brevity comes at the cost of the missing identification and partial-update details rather than being a model of tight writing.

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 destructive mutation with zero required parameters and no schema descriptions, the description should state how the target user is specified and whether the call is a partial or full replacement of the permission set. An output schema exists, so return values needn't be explained, but the input-side gaps are significant.

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 must carry the load, and it only restates the flag names without explaining what allow_decision, allow_pull, or allow_create actually grant. Worse, it omits fb_user_label, the parameter that identifies which user is being changed — arguably the most important one.

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 names a specific verb ('Update'), a specific resource ('one FB user's ... flags'), and enumerates the three mutable flags, so an agent knows exactly what changes. It falls short of 5 because it doesn't distinguish this from the closely-named sibling fb_users_update_label (which also updates a field on one FB user) or assets_update_account_permissions.

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?

There is no guidance on when to use this rather than fb_users_update_label, fb_users_refresh_routing, or assets_update_account_permissions, and no stated preconditions such as needing the user to already exist or requiring admin approval. The agent must infer the routing from the name alone.

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