Choose how to read a large file

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

The annotations declare readOnlyHint=true, but the description says it records the user's choice and that save_columns keeps columns on disk. Those are persistent state changes, which contradicts the read-only annotation.

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?

The description is dense but front-loaded with the critical trigger conditions. Every clause adds useful information about eligibility, choice semantics, caching, and the required follow-up call.

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 three-parameter tool with no output schema, it explains the trigger, the choice tradeoffs, the persistence option, and the next action. It does not describe what confirmation or return value the agent should expect, but the core call behavior is covered.

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%, so the description must carry parameter meaning. It explains both enum values for choice in detail and explains the effect of save_columns; only the file parameter remains unexplained, though its name is fairly self-evident.

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 and resource: it records the user's choice for a specific large file. It also clearly distinguishes the tool from the original data-reading tool by tying its use to a prior 'LARGE FILE' response.

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 gives explicit preconditions: only after a tool answered LARGE FILE and only after asking the user. It also tells the agent the next step: call the original tool again.

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