load_file_preview

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

The readOnlyHint annotation already declares this a safe read, and the description reinforces it with '(nothing is written)', which is consistent but not additive. It does add real behavioural context about detection vs. override of encoding/delimiter/quote/header/null markers, size-limit reporting, and the database-dependent CREATE TABLE branch, but says nothing about error cases (unreadable path, undecodable file) or how much of the file is sampled.

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?

Two sentences, front-loaded with purpose and non-mutation guarantee before the return-value inventory. The second sentence is a long comma-chained enumeration that is dense but each clause carries information; minor trimming of the return list would help scanability.

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 ten parameters at zero schema coverage and no output schema, the description does the heavy lifting by enumerating both accepted inputs and returned artifacts (sample rows, suggested types, formats, row estimate, size flag, CREATE TABLE and target). The main residual gap is failure behaviour and file-size or sampling constraints the agent would need to interpret an over-the-limit result.

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 carries the full burden, and it largely does: it names encoding, delimiter, quote (with the '"" = none' convention), header, null markers, decimal comma, formats as a {column: format name} override map, and table's default from the file name, plus the effect of database. Only 'path' is left implicit, and the defaults/nullable semantics for each optional parameter are not spelled out.

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: read the start of a data file on this computer, plus the scope qualifier 'for the Load file wizard (nothing is written)'. That is concrete and distinguishable from most siblings, but it never names or contrasts with the closest neighbours (load_file_info, load_file_browse, schema_explorer_preview), leaving the agent to infer the split.

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?

The phrase 'for the Load file wizard' implies the usage context — prepare an import before creating a table — and 'nothing is written' signals it is a safe preflight step. There is no explicit when-to-use versus when-not guidance, and no named alternative for inspecting a file's metadata or browsing directories.

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