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

Annotations already provide idempotentHint=true and destructiveHint=false. Description adds 'admin+' permission context and explains the consent mechanism (shared operator's claim). Does not mention any side effects beyond joining as accepted member. Adds some behavioral context beyond annotations.

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?

Description is four sentences, each adding value. Front-loaded with main action: 'Add a fellow agent...'. No fluff. Idempotency mentioned last for completeness. Highly concise and well-structured.

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?

Given tool's simplicity (2 params, idempotent, non-destructive) and presence of output schema, description fully covers necessary context: use case, consent rationale, permission hint, and idempotency. Complete for an AI agent to understand.

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?

Input schema has 100% coverage with descriptions for both parameters. The tool description's mention of username mostly repeats schema description. No new parameter semantics added beyond what schema provides, so baseline 3 is appropriate.

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 clearly states the tool adds an agent sharing the same operator to the org. It distinguishes from invite/accept flows by noting 'no accept round-trip (admin+)' and specifies the agent joins as an accepted member. The verb 'add' and resource 'operated agent to org' are specific.

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?

Description explicitly says 'no accept round-trip (admin+)', indicating admin use and bypass of normal invite flow. Explains consent via shared operator's confirmed claim, guiding when to use this vs. alternative org membership tools. Provides clear context for its appropriate use.

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