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

Annotations already declare readOnlyHint=true, so the safety profile is covered, and the description adds value by naming the returned fields (destination URL, transform config), which matters since there is no output schema. It does not mention error behavior (e.g., missing id) or auth requirements, so it stays at a solid but unremarkable 3.

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 return fields. The trailing API mapping ("GET /proxies/{id}") is mildly redundant but compact and does no harm.

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 read with full parameter coverage and readOnly annotations, the description covers what the tool does and what it returns, compensating for the absent output schema. Error and auth behavior are the only missing pieces.

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?

There is a single parameter with 100% schema description coverage, so the schema fully documents proxy_id. The description adds no format or syntax detail beyond the schema, matching the baseline of 3 when the schema does the heavy lifting.

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 gives a specific verb ("Fetch") and resource ("a single proxy") and even names the returned fields (destination URL and transform configuration). This implicitly separates it from the sibling basis_theory_list_proxies, though no alternative tool is named 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?

There is no explicit when-to-use guidance or mention of alternatives such as list_proxies or search_tokens. The agent must infer that this is the right tool when it already holds a single proxy_id.

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