get_subscription

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

Annotations only declare readOnlyHint=true; the description adds meaningful behavioral context beyond that (account prerequisite, API-key configuration, restart requirement, and the negative note about start_login). It discloses no return format or rate-limit behavior, but for a read-only getter the auth context is the salient trait.

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?

Front-loads the purpose sentence, then separates access prerequisites into a labeled ACCESS block, which is easy to scan. Slightly more text than strictly needed, but every sentence carries useful information.

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 parameterless read tool with no output schema and a single readOnly annotation, the description covers purpose plus the critical account/API-key prerequisites. The only omission is return shape, which is minor given the enumerated fields.

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?

With zero parameters and 100% schema coverage, the baseline is 4. There is nothing further for the description to disambiguate, and it introduces no parameter-related confusion.

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+resource ('Get the current subscription details') and enumerates the returned fields (plan, status, billing period, usage limits), so an agent knows exactly what this tool surfaces. It does not explicitly differentiate itself from near-siblings like get_usage or get_platform_summary, which keeps it at a 4.

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 ACCESS block gives concrete conditions for use: a Proof account is required, PROOF_API_KEY must be set and the server restarted, and it explicitly says start_login does NOT open this tool. This is actionable when/when-not guidance naming an alternative, though it stops short of describing broader routing vs other account tools.

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