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

Beyond the annotations, the description discloses key behavioral aspects: the two-step process for local file uploads, the 15-minute wait timeout, the necessity of a token, and the fact that supplying no arguments returns an upload link. It also clarifies that bytes cannot be sent directly, which is critical operational knowledge. This adds substantial context beyond the readOnlyHint=false annotation.

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?

Although the description is relatively long, it is densely informative with no wasted words. It follows a logical structure: purpose, supported formats, two usage modes, critical constraint, and downstream usage. Every sentence earns its place, and the information density is appropriate for the tool's complexity.

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 the tool's complexity and the absence of an output schema, the description fully covers the essential return value (URLs) and their use in other tools. It also addresses the two entry points, the token mechanism, and the warning about byte transmission. No critical operational detail is omitted, making it complete for an agent to invoke correctly.

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?

The input schema already describes each parameter thoroughly (100% coverage), but the description adds significant semantic context by explaining how token and file_url correspond to the two upload flows. It clarifies the optional filename default behavior and when to omit parameters, which goes beyond schema descriptions. This makes the parameter usage actionable.

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 clearly states the tool's purpose: 'Get a file into cnaps.ai so a flow can use it.' It specifies the resource (file upload) and distinguishes it from sibling tools by focusing on the upload process and listing supported formats. The verb 'get' is slightly ambiguous, but the context makes it clear this is about uploading/registering a file.

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 description provides explicit guidance on two distinct usage flows: passing a public URL vs. generating an upload link for local files. It also warns against an incorrect approach ('You CANNOT send bytes from the chat through MCP'), and explains how the returned URLs are used in create_flow or run_flow, giving clear context for when and how to invoke the tool.

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