Build an OAuth authorization URL

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds substantive behavioral context beyond that: it explicitly notes "Makes no network call" (a concrete, non-obvious trait) and explains the full side effect chain (browser open, user approval, redirect with code).

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 sentences, front-loaded with verb+resource, and every sentence earns its place by adding scope, flow, or a behavioral constraint. 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 local URL-builder with 100% schema coverage and no output schema, the description supplies everything an agent needs: what it produces, how it is used, what happens after redirect, and that it performs no network I/O. Nothing material 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%, so the schema already documents all four parameters including the CSRF role of `state` and the env-var fallbacks. The description adds the returned `code` query parameter detail but does not extend meaning on the input params themselves; 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 (build) and resource (the Pinterest consent/authorization URL) and clarifies the operational mode with "Makes no network call." It also distinguishes itself from the sibling pinterest_exchange_oauth_code by naming it as the next step, so an agent can place it in the OAuth flow without opening any 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?

Describes the usage flow explicitly: open in a browser, user approves, Pinterest redirects with a `code`, then exchange via pinterest_exchange_oauth_code. This gives clear context for when to call it, though it doesn't state prerequisites (e.g. needing a registered redirect_uri) or when-not-to-use beyond the implied sequence.

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