subscriptions_get_by_username

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

No annotations are provided, so the description carries the full burden. It states it's a read operation ('Get'), but doesn't disclose behavioral traits such as authentication requirements, rate limits, error handling (e.g., if username not found), or what 'subscription details' includes. This leaves significant gaps for an agent to use it effectively.

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 a single, efficient sentence that front-loads the core action ('Get subscription details') and specifies the method ('by username'). There is no wasted verbiage, making it easy to parse quickly.

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 no annotations and no output schema, the description is incomplete. It doesn't explain what 'subscription details' includes, potential errors, or how it differs from similar tools. For a read tool with one parameter, it's minimally adequate but lacks context needed for robust use.

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 100%, with the parameter 'username' fully documented in the schema. The description adds no additional meaning beyond implying the parameter is used for lookup, so it meets the baseline of 3 where the schema does the heavy lifting.

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 verb ('Get') and resource ('subscription details') with a specific lookup method ('by username'). It distinguishes from siblings like 'subscriptions_get_by_uuid' and 'subscriptions_get_by_short_uuid' by specifying the identifier type, though it doesn't explicitly contrast with 'subscription_info' which might be similar.

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?

No guidance is provided on when to use this tool versus alternatives like 'subscriptions_get_by_uuid' or 'subscriptions_get_by_short_uuid'. The description implies usage when you have a username, but it doesn't specify prerequisites, error conditions, or comparisons to sibling tools.

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