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

No annotations are provided, so the description carries the full burden. It discloses a genuine behavioral constraint: the path must resolve inside UPLOAD_DIR (default /shared/uploads) and paths outside are refused, plus the mutual exclusion of file_path and base64_data. However, it omits Odoo-side permission/auth requirements, size limits, and whether this creates a new ir.attachment record or overwrites existing ones, which matters for a mutation tool with zero annotation coverage.

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?

Front-loads the purpose in one line, then uses a tight two-bullet structure for the modes; no filler sentences. There is minor redundancy with the schema's UPLOAD_DIR constraint, but repeating a security-critical constraint in the description is defensible.

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?

Both input modes, the cross-tool routing to prepare_upload, and the directory jail are covered, and an output schema exists so return values need no explanation. The remaining gap is behavioral, not structural: auth requirements and write-side effects go unmentioned for a mutation tool with no annotations.

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 description coverage is 100%, so the schema already documents every parameter, including the mutual exclusivity of file_path and base64_data and the res_id/res_model dependency. The description restates the mode semantics but adds no syntax or value format beyond the schema, so the baseline of 3 is correct.

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 ('Upload a file attachment to Odoo via ir.attachment') and immediately enumerates the two supported input modes, so the agent knows exactly what the tool does. The distinction from sibling create_record is implicit in the attachment-only scope, and the prepare_upload reference further locates it in the toolset.

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 explicit mode-selection rules: use file_path when the file lives on the MCP server, base64_data when the file is not on disk (with a concrete example, 'image uploaded via Discord'). It names the alternative tool (prepare_upload) and the exact condition that selects it (remote server, client-side file), leaving nothing to inference.

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