form_lookup_external_resource

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds nothing beyond that - no note that results reflect live external/vRO state, whether empty results are possible, or what the returned object contains.

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 lines where one would do: the first sentence duplicates the second, and the HTTP path repeats the annotation title. The input-dependent clause is the only content-bearing part, but it is not front-loaded as the distinguishing 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 read-only lookup with full schema coverage and no output schema, the core facts an agent needs (read-only, idempotent, scoped by namespace/type/id) are all present via annotations plus schema. What is missing is domain context such as what an "external resource object" is relative to vRO types and projects.

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 schema documents all four parameters, and the description only weakly echoes it ("depending on namespace type and id") while omitting projectId. Baseline 3 is appropriate when the schema carries the parameter burden.

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 verb plus resource ("Retrieve external resource object"), but that largely restates the tool name form_lookup_external_resource. The only extra information is that retrieval varies by namespace/type/id, and there is no differentiation from the closely named sibling form_lookup_external_resources or form_get_external_value.

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?

No guidance on when this tool applies versus alternatives; the singular-vs-plural sibling (form_lookup_external_resources) is never mentioned, nor are prerequisites such as a valid project or namespace. The agent must infer the use case entirely.

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