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

With no annotations, the description carries the full burden and does well: it discloses the replacement semantics ('Replaces the account's earlier platform role'), the delayed effect ('Takes effect on the next request'), and the authentication/scope prerequisites. It stops short of stating whether the change is audited, reversible, or what a partial failure returns.

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?

Four short sentences, front-loaded with eligibility and scope before the operational detail. No filler, and each sentence adds a distinct fact.

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 two-parameter privileged mutation with no annotations and no output schema, the description covers access control, target identification, replacement behavior, and effect timing. It omits error conditions and whether existing sessions are affected, which is the only real gap.

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 compensate. It explains that 'email' identifies an existing account and adds the semantic constraint on 'role' that the enum alone cannot convey (who may grant which role). Format constraints (pattern, maxLength) remain schema-only, which is the right place for them.

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 — 'Give an existing account (by email) a platform role' — and the scope constraint in the same opening. An agent can distinguish this from platform_staff_revoke (removal) and platform_staff_list (read) without opening any 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?

Explicitly restricts callers ('Platform staff only (account session)', 'Requires the staff scope') and lays out the role-granting hierarchy (owners any role; admins support or finance). It does not name a sibling alternative for the inverse operation, but the context needed to decide whether to use this tool is present.

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