createDealAttachment

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

Without annotations, the description carries the full burden. It discloses that the file is not hosted by FUB, that the uri must be externally hosted, and that omitting the uri causes a 403. It also notes the system restriction. This covers key behavioral traits for a creation tool, though it doesn't specify what happens on success.

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 description is concise (three sentences) and front-loaded with the core purpose. The next two sentences add critical restrictions and behavioral notes without unnecessary details. Every sentence earns its place.

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 and no annotations, the description is fairly complete: it explains the tool's purpose, the system restriction, the key behavioral constraint (external hosting), and a specific error condition. It lacks a description of the return value or success response, which would marginally improve completeness but is acceptable.

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 schema covers all 4 parameters with descriptors, but the description adds important context: 'uri must point to an externally hosted file — FUB does NOT host uploads via this endpoint (omitting URI returns 403).' This clarifies a critical constraint beyond the schema, especially for the uri parameter. Other parameters (dealId, fileName, fileSize) are adequately described in schema.

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 'Attach an externally-hosted file to a deal' with a specific verb and resource. It distinguishes from siblings like createPersonAttachment (file to person) and deleteDealAttachment by specifying 'deal' and the external hosting nature. The restriction and key behavior are also clear.

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 prerequisites (requires FUB_SYSTEM + FUB_SYSTEM_KEY env vars) and critical usage notes (uri must be externally hosted, omitting uri returns 403). While it doesn't explicitly say when not to use this tool, it implies that it's only for registered systems and external files, which helps guide the agent.

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