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

With no annotations, the description carries the burden and does well: it discloses the authorization model (owner-only sharing, agent-as-approver), the capability boundaries of each role (viewer reads/exports, editor edits, neither re-shares), and that this tool also performs revocation. It does not cover idempotency, error behavior, or side effects of revoking beyond removing access.

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?

The first sentence front-loads both directions of the operation, and subsequent clauses each add distinct information on id formats, roles, and permissions. It is dense and slightly long for two primary sentences, but no sentence is 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 sharing tool with no annotations, the description supplies everything needed: who may call it, how to format the target actor, what each role grants, how an agent's grant maps to identity, and where to look up existing grants. An output schema exists, so return-value detail is legitimately omitted.

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 80% so a baseline of 3 applies, but the description adds real semantics beyond the schema: it enumerates the three actorId spellings accepted by this server (github:<login>, operator, agent:<fingerprint>), whereas the schema only offers 'e.g. github:octocat'. Role meanings are also expanded (viewer=read/export, editor=change) beyond the schema's terse 'editor or viewer'.

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?

States a specific verb and resource (share a design) and covers the inverse operation (take sharing back) in the same sentence. It also names ui_builder_design_access as the tool that lists existing grants, so an agent can distinguish it from its nearest sibling without opening a 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?

Explains the conditions for use: only the design's owner may share, and an agent acting under an approved grant shares as the approver. It routes to ui_builder_design_access for enumerating existing grants. It does not explicitly contrast with request_access/poll_access beyond mentioning the grant token, so it stops short of full when/when-not guidance.

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