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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false), and the description goes well beyond them: free-plan quotas (100 notes/images/links, 10 upload cap), no notification side effects, how to undo (drag card to trash), and the required Cotlet API key with app access. This is exactly the added behavioral value that lifts the score.

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 is front-loaded in the first clause, and each following sentence carries distinct information (granularity, quota, undo, auth). Slightly dense but no wasted sentences.

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-param write tool with no output schema, the description still tells the agent what comes back ('returns its ID'), the plan limits, the undo path, and the credential requirement. Nothing needed to call it correctly is missing.

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 board_id, file_name and file_base64 are already documented. The description implies a file is provided but adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 ('Image card from a file, placed on a board') and adds the per-call granularity ('Adds one image card per call and returns its ID'). Against the milanote sibling set (add_note, add_link, add_todo_list), the resource type cleanly separates this tool.

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 by the purpose rather than stated as an explicit when/when-not rule, and no alternative is named. The 'Nobody is notified, so it runs without asking' line gives useful context for autonomous invocation, but not selection guidance against siblings.

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