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

Beyond the annotations (readOnlyHint=false, destructiveHint=false), the description discloses that the originals are untouched and the result is a new list, that unmatched rows carry over, and that filled cells are unverified inputs requiring a quote and approval for downstream research. That downstream consequence is genuinely useful context an agent cannot get from the annotations.

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?

Four short sentences, front-loaded with the core action, then scope, then output behavior, then a downstream caveat. Dense phrasing ('counterpart rows', 'comparison hash') but no wasted text.

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 five-parameter mutation with no output schema and zero schema coverage, it explains the result shape reasonably (new list, retained unmatched rows) but never says what identifier or object is returned, and three of five inputs are unexplained.

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 0% across five required parameters, so the description must compensate and largely does not. It clarifies comparison_hash ('exact') and maps 'choices' to user-chosen pairs, but import_id, comparison_id, and name receive no meaning at all.

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?

The description uses a specific verb ('Fills empty cells into a new list') tied to a concrete source ('counterpart rows of the pairs the user chose'), which tells an agent exactly what the tool produces. It never names the adjacent steps (prepare_reconciliation, get_reconciliation) in the sibling list, so differentiation must be inferred from the name alone.

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?

'It takes the exact comparison hash' and 'the pairs the user chose' imply this runs after a comparison and a user selection, but no prerequisite or ordering against prepare_reconciliation is stated. There is no explicit when-not-to-use or alternative named, so usage is only implied.

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