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

Annotations provide only generic flags (readOnly=false, destructive=true, idempotent=false, openWorld=true). The description adds concrete behavior: a join link is emailed and 'is never returned here,' explaining the external side effect and managing output expectations. This is valuable beyond annotations, though it does not cover failure/duplicate behavior.

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 with no unnecessary words: action, effect, prerequisit, and return behavior are each given their own concise sentence. Information is front-loaded and every 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 one-parameter tool with no output schema, the description covers purpose, admin requirement, email delivery, and the notable absence of the link in the response. Minor gaps exist around duplicate invites and error cases, but they are unlikely to prevent correct invocation.

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%; the email parameter is fully described as 'The colleague's email address.' The description clarifies that 'by email' is the delivery mechanism, but this does not materially add to the schema. Baseline 3 applies.

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 a specific verb ('Invite'), a resource ('colleague to... workspace'), and the mechanism ('by email'), clearly distinguishing it from read-only siblings like list_members. It is immediately obvious what the tool does.

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?

The description states the key prerequisite 'Requires an admin,' giving an agent clear condition for when the call is permissible. There are no true alternatives among siblings, so explicit exclusions are unnecessary, but the usage context is otherwise implied rather than spelled out.

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