Get localStorage

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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds valuable behavioral details: values truncated to 200 characters, per-origin scoping, empty results on about:blank, and exclusion of sessionStorage. These go beyond the annotation signals and set clear expectations.

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 compact and well-structured: three short paragraphs each serving a distinct purpose (purpose, truncation/alternative, scoping caveat). Every sentence contributes meaningful information with no redundancy.

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 the zero-parameter, read-only nature and the presence of an output schema, the description covers the essential non-obvious aspects: truncation, origin scoping, about:blank behavior, and the evaluate_script alternative for full values. It is thorough and leaves no critical gaps.

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 schema has zero parameters, so the baseline is 4. The description adds context about the implicit scope (current page's origin) and the truncation behavior, which is useful even though there are no formal parameters.

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 clearly states the tool's function: 'Read all localStorage entries for the current page's origin.' This uses a specific verb (Read), resource (localStorage entries), and scope (current page's origin). It also distinguishes from siblings by explicitly excluding sessionStorage and pointing to evaluate_script for reading a single full value.

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 description provides explicit usage guidance: 'for one entry in full use evaluate_script with ...' and warns about about:blank, implying a prerequisite of navigation. The note that sessionStorage is not included further clarifies when to use this tool versus alternatives.

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