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

The readOnlyHint annotation already establishes this as a safe, non-mutating read. The description adds content-level context about what the resource contains (destination URL, transform config), which is genuinely useful, but says nothing about 404/not-found behavior, permissions, or response shape.

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 action and resource. The trailing 'Basis Theory: GET /proxies/{id}' is mildly redundant but compact and maps the tool to the underlying API endpoint.

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-resource read with one well-documented required parameter, no output schema, and a readOnlyHint, the description covers enough: what it returns and the endpoint. Missing only not-found/error semantics, which is a minor gap at this complexity.

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?

Only one parameter (proxy_id) and the schema documents it at 100% coverage, so the schema carries the burden. The description adds no format, sourcing, or lookup guidance beyond what the schema already says.

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 (Fetch) and resource (a single proxy) and even names the payload fields (destination URL and transform configuration). It implicitly contrasts with basis_theory_list_proxies by saying 'single', though it does not name the sibling explicitly.

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 implied: you fetch one proxy when you have its id. There is no explicit when-to-use vs. when-not guidance (e.g., 'use list_proxies to discover ids first'), and no stated prerequisites or error conditions for an unknown id.

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