get_disk_io_metrics

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

With no annotations, the description carries the full burden. It discloses that the tool reads from /proc/diskstats, skips loop/ram/zram devices, and is fatal only if unreadable. This is transparent about data source, filtering, and error behavior—excellent context beyond the basic read-only claim.

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 the core purpose, followed by behavioral details and usage guidance. Every sentence adds value with no redundancy or filler.

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?

Given zero parameters, an output schema exists, and sibling tools provide contrast, the description is fully complete. It covers what the tool does, how it behaves, when to use it, and alternatives—enough for an agent to select and invoke it correctly.

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?

The tool has zero parameters, so the baseline is 4. The empty input schema is fully documented, and no parameter details are needed. The description concentrates on output semantics rather than parameter meaning, which is appropriate.

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 states a specific verb ('Returns') and resource ('per-device disk I/O') with fields ('reads, writes, sectors, and timings'). It distinguishes from siblings by explicitly mentioning per-process I/O as a different tool (get_top_io_processes).

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?

Explicit guidance is given: 'Use for storage performance; get_top_io_processes for per-process I/O.' This tells the agent when to invoke this tool and names the alternative for a different use case. The read-only and failure conditions also help clarify appropriate usage.

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