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

Beyond the readOnly/idempotent annotations, it discloses that it reads stored results only, never extracts, never bills, and requires an API key — cost and auth behavior an agent cannot infer from annotations. It also summarizes what the response 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?

Front-loaded with the core purpose, then behavior, then routing — good ordering. Slightly dense with the embedded UCM definition and return-field listing, but each clause carries usable information.

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 an output schema present and full param coverage, the description covers what remains: scope, cost/read-only behavior, auth requirement, and sibling routing. An agent has everything needed to call it correctly.

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% (limit and search are fully documented in-schema), so baseline is 3. The description mentions 'how many runs it has and when it was last run' but says nothing about limit or search semantics beyond what the schema already provides.

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+resource: listing datasheets that have a UCM digital twin, and defines what the twin contains (pins, rails, interfaces, registers, limits). It is clearly separable from datasheetvend_get_component_twin (fetch one) and datasheetvend_build_component_twin (create one).

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 routes: 'Pass a returned name to datasheetvend_get_component_twin' and 'To twin a datasheet the account has not extracted, use datasheetvend_build_component_twin.' Both the next-step alternative and the when-not condition are named.

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