set_working_directory

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

With no annotations, the description carries the full burden and does disclose a real side effect that nothing else declares: "Creates the directory if it doesn't exist," i.e. this is a filesystem mutation, not a pure setting. It also documents tilde expansion and path-resolution semantics. It does not state error behavior for invalid/unwritable paths, or whether the setting persists across sessions — the remaining gaps keep it from a 5.

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 primary effect, and each one adds a distinct fact (resolution rule, tilde support, directory creation). No filler or repetition of the title.

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 one-parameter, no-output-schema tool this covers purpose, side effects and path semantics adequately. Missing only failure modes (nonexistent parent, permissions) and whether the call returns the resolved absolute path, which would complete it.

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?

Single parameter at 100% schema description coverage, so the schema already defines `path` and its tilde support; the description only restates the ~ behavior. Baseline for a one-parameter tool with full coverage is 4.

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?

Specific verb+resource ("Set the working directory for file operations") with the scope of effect stated immediately ("All paths are resolved relative to this directory"). No sibling tool in the list manages a working directory, so no differentiation is required and the agent can identify this unambiguously.

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 second sentence gives the operative context that tells an agent when this matters — every subsequent path resolves against it — which implies it should be called before relative-path file operations. There are no explicit exclusions or named alternatives, but none exist among the siblings, so the missing piece is minor.

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