Get subscription by ID

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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds a genuinely new behavioral fact — OAuth integrations require the subscriptions:read scope — which is exactly the kind of context annotations cannot carry. Return-shape behavior is left to the schema's expand parameter.

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?

Three short, front-loaded sentences with no filler. Minor waste: 'Reads account data' largely restates the readOnlyHint annotation, so the space could have carried usage guidance instead.

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 simple single-resource getter with four well-documented params and no output schema, the description covers identity, safety context, and auth scope. It could still note whether the account parameter is required in multi-account setups, but nothing critical is missing.

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%: both required IDs, the account selector, and the expand enum are fully documented in the schema. The description adds no syntax, format, or semantics beyond that, so the baseline 3 applies.

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 (Get) plus resource (subscription) and an identifier qualifier (by ID) that immediately separates it from the sibling get_subscription_by_email and from list_subscriptions. An agent can select it without opening the schema.

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?

Usage is only implied: retrieve a single subscription when you already hold its ID. No when-to-use/when-not guidance and no alternatives (e.g. get_subscription_by_email, list_subscriptions) are named. The auth scope note is a prerequisite, not routing guidance.

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