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

Beyond the annotations, the description adds substantial behavioral context: trial duration, resource limits, read-only access, no-card requirement, email verification flow, and explicit handling instructions for the statusToken (“Keep the limited statusToken in MCP client state; never paste it into conversation text”). This gives an agent important operational and security guidance it could not infer from the schema or annotations alone.

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 sentences with no fluff; the first sentence carries the core action and constraints, and each following sentence adds distinct value. Security instructions are concise and actionable.

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?

The description covers trial limits, verification flow, and statusToken handling, while the output schema presumably covers return values. However, with zero parameter documentation and required fields like runtime and projectUrl undefined, an agent still lacks enough information to construct a correct invocation confidently.

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 0%, so the description must compensate. It does not define the required inputs projectUrl or runtime, nor the optional locale or company. It offers only indirect clues: idempotencyKey maps to “idempotent” and email receives the verification URL. This is insufficient for six undocumented parameters.

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?

Description states a precise action (“Start an idempotent 14-day trial”) and distinguishes the resource by calling it a “real” project, which separates it from siblings like start_sandbox. It also enumerates concrete limits (one project, 2,000 units, three provider connections, read-only), so an agent can tell exactly what this 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 phrase “real DigitalPublic trial” and “real project” imply this is the tool for a genuine trial rather than a sandbox, and “No card is required” is a clear adoption condition. It does not explicitly name alternatives or say when not to use it, but the context is strong.

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