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

Discloses the key is never returned in the tool response but emailed, describes side effects (email send, re-send at most once/day), and notes free-tier limits. This goes well beyond the sparse annotations and gives the agent accurate expectations.

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?

Every sentence carries operational value—action, triggers, constraints, delivery, limits, idempotency behavior—with no filler. The key action is front-loaded.

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 single-parameter tool with no output schema, the description covers input requirements, output behavior, side effects, limits, and duplicate handling. Nothing essential is missing for correct invocation.

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?

Even with 100% schema coverage, the description adds critical provenance constraints on the email parameter: it must be given explicitly in this conversation, never guessed/reused, and must belong to the user. This materially changes how the agent selects the value.

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 ('create'), resource ('free personal PropLine API key'), and delivery mechanism ('EMAIL it'). Clearly distinguishes from sibling read/export/price tools, none of which create keys.

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?

Provides explicit trigger conditions (shared-demo rate limit, redacted paid field, user asks how to get a key) and explicit exclusions (never guess, reuse, or sign up third party). No alternative tool exists among siblings, so the when-to-use guidance is sufficient.

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