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

Annotations already declare the mutation/idempotency/read-write profile, and the description layers on genuinely new behaviour: permission gating to owner or admin, PATCH-style semantics where omitted fields are untouched, https-only URLs, and the empty-string convention that clears the shared folder. It does not say what happens with an invalid tag length or whether the tag must be unique, which are the remaining behavioural gaps.

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 short sentences, front-loaded with the resource and the settable fields before format constraints and permissions. The opening sentence is dense with parentheticals and colons but nothing is redundant; there is no filler.

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 five-parameter, zero-required mutation with no output schema, the description covers permissions, partial-update behaviour, value formats and the removal convention — enough to call it correctly. Return values and validation failure modes are the only missing pieces, and no output schema exists to absorb them.

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 only 40%, so the description has to carry weight and largely does: it constrains tag to 2-3 letters, colour to #rrggbb, sharedFolderUrl to https with an empty string as the removal sentinel, and ties workspaceId to the scoped client. Only idempotencyKey lacks description-side elaboration, and the schema already documents it thoroughly.

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 the resource (a client/workspace's agenda appearance) and enumerates exactly the three attributes it sets: a 2-3 letter tag, a hex colour and a shared-folder link. The verb is implied by the title rather than the body, and it does not explicitly contrast with near neighbours like update_agenda_item or create_workspace, but an agent can tell what it writes.

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 real precondition ('Owner or admin only') and a partial-update rule ('Only what you pass changes'), which tells the agent this is a targeted patch rather than a full replace. It stops short of naming when to use this versus the sibling tools that also touch agenda items or workspaces, so the routing is inferred.

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