subscriptions_get_by_user_id

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds nothing further: no behavior when the user has no subscription, no error semantics, no note on what the subscription payload contains. With the annotation bar already met, the description contributes no extra behavioral context.

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?

A single four-word sentence with the lookup key front-loaded and no filler. It is efficient, though the brevity borders on under-specification rather than disciplined conciseness.

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 tool with no output schema and annotations covering safety, the description is minimally adequate. It is missing routing context among the several subscriptions_get_* siblings and any note about lookup failure, but the low complexity keeps the gap modest.

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% and the single parameter is documented in the schema, so the baseline of 3 applies. The phrase 'by User ID' merely restates the parameter rather than adding format, validation, or lookup-key semantics beyond what the schema provides.

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 specific verb (Get) and resource (subscription) plus the lookup key (User ID), which implicitly distinguishes it from the sibling lookups subscriptions_get_by_username and subscriptions_get_by_short_uuid. It never names those alternatives explicitly, so it stops short of full sibling differentiation.

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?

There is no when-to-use guidance, no exclusions, and no mention of the sibling variants by username or short UUID. The agent must infer from the name alone that this tool applies when a numeric user ID is available.

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