render_auth_link

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

With no annotations, the description carries the full burden and does so well: it discloses this is a local computation with no HTTP request, clarifies that `qr_text` is rejected, and warns that QR text rows stop scanning if separated by blank lines or wrapping. These are behavioral details an agent needs to use the tool safely and correctly.

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?

The main purpose and key safety constraint ('no HTTP request') are front-loaded, and the longer agent-usage paragraph is dense rather than padded: every sentence earns its place by preventing a real misuse. The nested details are complex but justified by the need to route the correct link field from many sibling tools.

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?

Given no output schema, the description still explains what the agent will produce: a clickable link plus QR code inside a fenced code block. It also covers the edge case where only `qr_text` is available, which is essential for correct behavior in this domain. The description is complete for a simple local render tool with tricky input-source rules.

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?

Although the schema already covers the parameters 100%, the description adds high-value meaning for `url` by mapping it to concrete upstream fields and by explicitly excluding `qr_text`. It also clarifies the optional `label` role implicitly through the schema example; the description's source-field guidance goes well beyond the schema's generic 'e.g. a deep_link response field.'

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 opens with a specific verb and resource: 'Render an authorization or verification URL as a clickable link followed by a scannable QR code inside a fenced code block.' It also distinguishes this local formatting tool from network or fetch tools by stating 'no HTTP request is made.' This is enough to tell it apart from sibling verification/render tools.

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 'Agent usage' section explicitly tells the agent which link fields to pass from which earlier tools and channels, and even names the exact fields (`deep_link`, `challenge.deep_link`, `telegram_deep_link` / `whatsapp_deep_link`). It gives a clear when-not: 'Do NOT pass `qr_text` to this tool,' with an explicit alternative of printing `qr_text` verbatim in a fenced code block.

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