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

Annotations only declare the safety profile (not read-only, non-destructive, closed-world). The description adds genuinely new behavioral context: files go into a processing/approval queue rather than being stored directly, and processing consumes account credits — an important cost side-effect not captured anywhere else. It still doesn't say whether the upload is synchronous or what happens on rejection.

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?

Two tight sentences with the action and accepted formats front-loaded, followed by the queue/credit consequence. No filler; could arguably be one clause shorter but every sentence carries information.

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 3-parameter upload tool with no output schema, the description covers the action, accepted inputs, downstream workflow, and the credit cost. The main gap is the return value (e.g. a document/queue ID) and any file-size limits, but overall it is complete enough 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?

Schema coverage is 67% and all three params are required and documented in the schema. The description reinforces the accepted MIME types (PDF/JPG/PNG) and that content is base64, but adds no syntax, size-limit, or prefix details beyond what the schema already states. 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 (nahraje/upload) plus the resource (uctenku nebo fakturu) and the accepted formats, and explains the destination (queue for processing and approval in the dashboard). It clearly distinguishes itself from read-side siblings like list_documents or get_document, though it doesn't name any alternative explicitly.

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?

Usage is implied rather than stated: the agent can infer this is the tool for submitting a receipt/invoice file, and the mention of 'fronta ke zpracovani a schvaleni' hints at the async workflow. There is no explicit when-to-use vs. when-not-to-use guidance or named alternative (e.g. create_invoice_draft for pre-approval drafts).

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