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

Beyond readOnlyHint/openWorldHint=false, it discloses cost semantics ('costs one upstream request, always'), that the jurisdictions preview rides the same request and is free, and a privacy guarantee ('Nothing about your model is sent here and no argument carries one'). It also enumerates the returned advisory fields (tested_model_families, model_notice), which annotations cannot express.

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?

It is front-loaded with 'Preflight.' and ordered by importance, but repeats the single-request cost point twice ('Costs one upstream request, always' and 'rides this same request rather than spending a second one', then again in the jurisdictions property). A modest trim would earn a 5.

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?

With no output schema, the description compensates by enumerating what is returned (key status, allowance and reset, library currency, plugin currency, tested_model_families, model_notice) and the null-means-unknown caveat. An agent has enough to call it correctly and interpret the result.

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 coverage is 100%, so the baseline is 3, but the description adds real decision-relevant meaning: the optional jurisdictions preview does not increase cost, and omitting client_version makes update_available null — explicitly not a currency signal. It stops short of restating formats for jurisdictions slugs, which the schema covers.

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 names a specific verb and resource — reporting key reachability/validity, allowance remaining and reset time, law library freshness, and plugin currency — and explicitly positions itself against siblings with 'Call this first'. An agent can distinguish it from get_law, run_lint, and claim_trial_key without opening a schema.

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 an explicit ordering instruction ('Call this first') plus the concrete failure mode avoided ('a missing key otherwise surfaces several steps later as a rejected tool call'). That is a when-to-use rule with a stated consequence, which is more than most siblings likely need.

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