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

Despite annotations marking this as destructive, the description goes well beyond them: it discloses the same-name overwrite behavior, the ~7 MB pre-encoding size ceiling, filename character restrictions, and .exe rejection. This is exactly the mutation context an agent needs before calling.

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?

One dense paragraph, front-loaded with what the tool does and its user-visible effect. Every sentence carries information, though the return-value and connection clarifications at the end could be broken out for easier scanning.

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?

With no output schema, the description compensates by naming the returned fields (file id and pathInNotebook) and explaining how each is used downstream. Combined with limits and overwrite semantics, an agent has everything needed to invoke this 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 100%, so the baseline is 3, and the description adds real meaning on top: the size limit applies to contentBase64, and name must carry an extension and avoid reserved characters. It stops short of 5 only because the parameter details are interleaved in prose rather than mapped explicitly.

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 ('Put a file into a project's files') plus the resulting state ('teammates can open and download it'). It clearly contrasts with sibling operations like fastero_read_file, fastero_delete_file, and fastero_create_file_connection.

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?

Gives concrete usage scenarios ('a CSV from the user's machine, or a report you produced') and explicitly routes to fastero_create_file_connection when a queryable connection rather than a plain file is needed. It doesn't state explicit when-not-to-use conditions, keeping it just short of a 5.

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