get_carrier_subscriber

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

With no annotations, the description fully discloses behavior: testing limitations, exact return behavior (subscriber verbatim), error propagation (404 verbatim), and parameter semantics. This goes beyond a minimal description and gives agents confidence in edge-case handling.

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 compact, front-loads the core action, and every sentence adds value. Testing caveats, return behavior, and parameter meanings are all covered without verbosity.

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?

Given the presence of an output schema, the description need not detail return fields, but it adds critical non-obvious info: hermetic testing status, verbatim passthrough, 404 surfacing, and key_label routing. For a simple get-by-ID operation, this is complete.

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 0%, but the description fully explains both parameters: subscriber_id as the UUID from the sibling list tool, and key_label as an optional API-key routing label. This compensates entirely for the lack of descriptive text in 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 states a clear action ('Get') targeting a specific resource ('Carrier / ISP Fabric subscriber') by ID, which distinguishes it from sibling list tools like list_carrier_subscribers. It also names the required parameter upfront.

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 context: the subscriber_id comes from list_carrier_subscribers, and the optional key_label is explained. However, it does not explicitly state when to use this tool versus alternatives beyond identifying the source of the ID, so it misses a clear exclusion statement.

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