add_blacklist

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

With no annotations, the description carries full burden. It discloses idempotency (re-adding returns 200) and the effect on send-sms. This goes beyond the schema but lacks details on auth, rate limits, or side effects. Still, it provides key behavioral traits.

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 two sentences plus a reference link, with no unnecessary words. Every sentence adds value: purpose, idempotency, limit per request.

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 the core operation, idempotency, and the relationship to send-sms. It lacks output format details (no output schema), but for a simple add operation this is acceptable. The reference link provides additional context.

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?

The schema provides a description for the 'number' parameter with accepted formats, so the description adds only 'one number per request.' With 0% schema description coverage counted, the tool description compensates partially but does not add significant extra meaning beyond the schema.

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 clearly states the action ('adds one phone number'), the target resource ('to your account's blacklist'), and the effect ('so it is skipped by send-sms'). It distinguishes from sibling tools like delete_blacklist (removal) and get_blacklist (listing).

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 description mentions idempotency and 'one number per request,' which are important usage constraints. However, it does not explicitly state when to use this tool versus alternatives (e.g., delete_blacklist, get_blacklist), though the context of blacklist management makes it implicit.

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