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

Beyond the annotations (which only declare non-readonly, non-idempotent, non-destructive), the description discloses the persistent side effect (file saved among the company's underlag), the pool behavior when voucher_id is omitted, the required 'upload' permission, and the return payload. This is exactly the behavioral context annotations cannot carry.

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?

Purpose first, then routing rules, then return values, side effects and the permission requirement — every sentence carries distinct information with no filler, despite the length the content is front-loaded and scannable.

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?

There is no output schema, but the description enumerates the return fields (id, filename, filetype, size, voucher-id or null), states the side effect, links all four sibling alternatives and the permission prerequisite. An agent has everything needed to select and invoke it 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?

With 100% schema coverage the schema already documents all four parameters, so the baseline is 3. The description still adds meaning beyond the schema by tying content_base64 to the 'small file' constraint and explaining that omitting voucher_id routes the file into the underlag pool for later linking with attach_underlag.

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 and resource ('Laddar upp en liten fil ... som underlag och kopplar den valfritt till ett verifikat') with the distinguishing scope condition (small, base64-encoded, optionally linked to a voucher). An agent can tell it apart from attach_underlag, create_underlag_upload and upload_underlag 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?

Explicit when-to-use ('Använd när filen inte redan finns i Kvickd och är liten nog att skicka base64-kodad') followed by three named alternatives with the exact condition that selects each: existing file -> attach_underlag, large file -> create_underlag_upload, reconciliation -> upload_underlag. Nothing is left to inference.

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