Set Tracker entity direct permissions

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

Annotations already declare idempotentHint=true, destructiveHint=false and readOnlyHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the update is additive/subtractive only for the named principals while everything else is preserved, and the call returns the resulting rights. The 400-on-permissionSources restriction lives only in the schema body description, not the tool description.

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?

Three tight sentences: behavior and partial-update semantics first, the parameter mapping second, the return value and prerequisite last. No filler and nothing important buried at the end.

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-parameter mutation with a deep nested body, no output schema and idempotent annotations, the description supplies the missing pieces: partial-update semantics, return value, and the recommended preceding read. The one gap is the permissionSources rejection, which is only discoverable from the nested body schema.

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 100%, so the baseline is 3, but the description adds meaning the schema does not: it enumerates the valid roles (AUTHOR, OWNER, CLIENT, FOLLOWER, MEMBER) and clarifies that users may be given as logins or ids. These are real usability gains on top of structured fields.

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 precise verb pair (grant/revoke) and resource (an entity's direct rights), and the word 'direct' explicitly separates it from the sibling tracker_entities_permissions_update, which handles the non-direct permission model. An agent can route correctly without opening the schema.

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 gives a clear read-before-write workflow ('Read them first with entities_permissions_get_direct') and states the partial-update contract ('the rest stay as they are'). It stops short of an explicit when-to-use-this-vs-tracker_entities_permissions_update comparison, so it is strong but not complete.

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