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

readOnlyHint=true already establishes this as a safe read, so the description only needs to add context. It usefully discloses the return payload (templates and workflows) and the identifier requirement, but says nothing about size, pagination, or what happens if both eid and slug are supplied.

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 short sentences, front-loaded with purpose and return contents. The trailing 'GraphQL query: organization' is implementation detail that aids debugging but is not strictly necessary for tool selection.

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?

With no output schema, the description carries the burden of describing returns and does so at a high level (casts and welds). Combined with a 100%-covered two-parameter schema and a read-only annotation, an agent has enough to call it correctly; only the return shape and pagination are underspecified.

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 baseline would be 3, but the description adds real value the schema cannot express: 'at least one is required' captures the either/or constraint that the zero-required-parameter schema leaves ambiguous. The slug's provenance (from anvil_current_user) is left to the schema description.

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 ('Fetch an Anvil organization') and adds what comes back (casts and welds), which is more than the title. It implicitly supersedes the narrower siblings anvil_get_cast and anvil_get_weld by returning both, but never names them, so the agent must infer the distinction.

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 only guidance given is identifier selection ('Provide either its slug or its eid'), which is invocation guidance rather than when-to-use guidance. There is no statement about when to prefer this over anvil_get_cast or anvil_current_user, so routing is left to inference.

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