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

Annotations already declare non-read-only, open-world, non-destructive behavior; the description adds real value beyond them with the 409 conflict condition, the validation pipeline (format, uniqueness, disposable/deny-list), and the 422 failure mode. It stops short of stating what happens to existing aliases or any rate limits.

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 compact sentences with no filler: purpose first, availability constraint and its failure code second, validation outcome third. Every clause is an actionable 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?

An output schema exists, so return values need no prose. For a 3-parameter creation tool with a non-trivial eligibility gate, the description covers purpose, precondition, and error semantics; nothing an agent needs before calling is missing.

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%, so the 3 (entity, format, and context-string) parameters are baseline-documented. The description goes beyond the schema by characterizing address validation (format, uniqueness, disposable/deny-list) and reinforcing that the alias leaves the primary address unchanged. The mandatory `context` parameter is left entirely to the schema.

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: 'Add an alias email address to a teammate.' The alias framing distinguishes it from create_teammate (which adds a teammate) and update_email (which mutates an existing address), so the agent can route without opening schemas.

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 states the when-not condition: only usable when the workspace manages its own team list, and that a directory integration (Google, Microsoft, Zoho Mail) yields a 409. It does not name the alternative path (e.g. sync_teammates or list_integrations) for directory-driven workspaces, which is the only gap.

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