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

Annotations already mark readOnly/idempotent/non-destructive; the description adds that the code expires, is read-only, and discloses how tool-call arguments are stored. This is valuable context beyond the annotations and contains no contradiction.

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?

The description is longer than average but each sentence earns its place: trigger condition, returned plan contents, interaction guidance, and privacy warning are clearly separated. It is front-loaded with the most important usage rule.

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 one-parameter read-only tool, the description fully covers when to call it, what it returns, how to behave with the results, and privacy constraints. No output schema is needed because the return contents are enumerated clearly.

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% for the single code parameter. The description adds value beyond the schema by explaining the code's prefix (sca_), where the user obtains it, its read-only/expiring nature, and that personal data or secrets must not be sent.

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 specific verb and resource: retrieve the user's own Stackcut savings plan from an agent code. It also states the precise trigger ('only when the user gives you a Stackcut agent code'), which distinguishes it from recipe/build/plan siblings.

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 says when to use: only when the user provides a sca_ code copied from 'Send to my agent'. It also gives follow-up guidance (walk through from biggest saving, ask before cancelling/purchasing) and warns not to send secrets.

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