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

readOnlyHint=true already tells the agent this is a safe read, so the description's job is lighter. It adds the endpoint mapping (GET /applications/{id}) and the shape of what comes back (type plus permission list), which is useful context, but there is no note on 404 behavior or scope/tenant requirements.

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?

Two short sentences, front-loaded with the purpose and followed by the endpoint reference. No filler or redundancy.

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 single-parameter read tool with an annotation covering safety and no output schema, the description is nearly sufficient: it names the resource and the returned fields. Only minor gaps remain, such as error behavior when the id does not exist.

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 schema description coverage at 100% and a single documented parameter, the schema already carries the semantics. The description adds nothing about id format or where the id originates, so baseline 3 is appropriate.

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 and resource ('Fetch a single application') and notes the payload contents (type and permission list), which cleanly separates it from basis_theory_list_applications. It stops short of explicitly naming the list sibling, so differentiation is implied by 'single' rather than stated.

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: the required application_id makes clear this is the by-id lookup, contrasted implicitly with the list endpoint. There is no explicit when-to-use/when-not guidance or named alternative for retrieving many applications.

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