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

With readOnlyHint=false, the description usefully explains why: it writes a local reading back onto the domain, and states that re-running is safe ("run this again any time"), matching idempotentHint=true. It also pre-empts a likely misinterpretation by saying the result is never a compliance verdict. It does not say what happens to a prior reading when a new one is recorded, which is the one material behavior left implicit.

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?

Purpose and side effect are front-loaded, and every following sentence carries real constraint value. The environment paragraph is somewhat repetitive ("does not stand in for it" restates the cloud-vs-local point), costing a little tightness but not clarity.

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?

The description covers the two things an agent could get wrong on this tool: where it can legally run, and what the result must not be interpreted as. Return values are handled by the output schema, and the nested reading object is explained in the schema, so nothing essential is missing.

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 url, seenAt, reading, and domainId are already documented, including the instruction that reading is exactly what the gcm check command returned. The description adds no parameter-level detail beyond that baseline, which is acceptable but not additive.

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 opens with a specific verb-and-resource pair ("Reads Google Consent Mode on one of your CookiePal domains") and adds two concrete behaviors: it names the problem if one exists, and it records the result on the domain. That is unmistakably distinct from siblings such as plan_check, verify_installation, or start_scan without needing to compare schemas.

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?

It gives clear usage context ("Run this again any time to re-check") and, more importantly, hard environmental exclusions: it must run from the CookiePal plugin in Claude Code on the user's own machine (terminal/desktop/IDE), and claude.ai, Claude Code on the web, or any external crawler cannot substitute. What it lacks is a direct pointer to which sibling to use when the local plugin is unavailable, leaving that inference to the agent.

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