permissions_update

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

Annotations indicate write operation (readOnlyHint=false). The description adds the merge semantics, explaining that entries are added/updated without describing removal. This provides useful context beyond annotations, though it doesn't detail error handling or side effects.

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?

Single sentence that conveys the core functionality efficiently. No wasted words; it is front-loaded and easy to parse.

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?

Given the presence of an output schema (indicated), the description provides the key behavioral distinction (merge vs replace). However, it lacks details on error conditions, default behavior for existing entries, or prerequisites. Moderate completeness.

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% with clear descriptions for all three parameters (object_type, object_id, access_control_list). The description adds no additional parameter-specific meaning beyond the schema, so baseline score 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 uses 'Patch the ACL' and 'merged into the existing ACL', clearly indicating an update operation that adds or updates entries without replacing the entire list. This distinguishes it from sibling tools like permissions_set (likely replace) and permissions_delete.

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 implies usage for adding/updating ACL entries via merge behavior, but does not explicitly state when to use this vs alternatives (e.g., permissions_set for full replacement). The guidance is implicit and could be clearer.

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