windirstat_scan

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

With no annotations provided, the description carries the full burden and does well: it declares the operation read-only and explicitly says 'Never deletes anything,' which is exactly the safety signal an agent needs before touching C:\. It also discloses the two classes of output (cleanup candidates and largest files). It stops short of disclosing performance characteristics – a full-drive scan is likely slow – or any permission requirements.

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, both earning their place: the first states what happens, the second states the payoff and the safety guarantee. The read-only assurance is front-loaded as a parenthetical so the agent sees it before the return-value detail.

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-parameter, no-output-schema tool with zero annotations, the description covers safety (read-only, never deletes), the two result categories, and the target resource. What's missing is any hint about scan duration or scaling on large drives, which an agent scheduling work would want. Overall sufficient to call correctly, shy of exemplary.

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 all three parameters (path, top, min_mb) are already fully documented in the schema, including defaults and an example path format. The description only loosely gestures at them ('cleanup candidates', 'largest files') without adding new semantics. Baseline 3 is correct when the schema does the heavy lifting.

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?

Names a specific verb ('scan'), a specific resource ('a drive or folder'), and the underlying engine (WinDirStat), then states what the caller gets back: cleanup candidates and largest files. This is far more than a restatement of the tool name and lets an agent decide instantly whether this tool matches the task.

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 rather than stated: the tool scans drives/folders and surfaces cleanup candidates, which suggests 'use when looking for space to reclaim.' There is no explicit when-not guidance, no prerequisites (permissions, admin rights), and no mention of cost/time for scanning an entire drive versus a subfolder. Adequate but with real gaps.

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