Describe engine & server capabilities

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral value beyond that: 'network is always \'none\'' discloses connectivity behavior, 'Offline preflight (no archive needed)' clarifies it never touches archives, and it discloses that certain engine exports are deliberately not exposed (with why). No contradiction with annotations.

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 key differentiator ('Offline preflight (no archive needed)') is front-loaded, and the usage guidance is placed at the end, but the body is a single long run-on enumeration that is dense and hard to parse quickly. For a capability-discovery tool the enumeration is genuinely useful, but it would benefit from structuring the list of returned items.

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 an output schema present, return-value explanation is already handled structurally. The description covers an unusually complete scope for a capability tool: versions, deflate tiers, runtime codecs, worker threads, registry, limits, operator ceilings, server caps, sandbox/cache state, error/diagnostic codes, and unexposed exports — plus the 'network is always none' note. Nothing an agent needs to interpret capabilities or refusals 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%, with both 'fields' (dot-path projection with _meta.unmatchedFields reporting) and 'verbosity' (full/summary enum) already well-documented in the schema. The description adds no parameter-specific detail beyond the schema, so the baseline 3 applies — the schema does the heavy lifting.

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+resource ('Offline preflight') and enumerates a precise, concrete set of what it returns (versions, deflate tier, codecs, limits, ceilings, error codes, unexposed exports). The 'no archive needed' note and the phrase 'server / engine capabilities' clearly separate it from sibling zip-manipulation tools that operate on archives.

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 closing guidance 'Call it first in a session, or whenever a cap / ceiling refusal needs interpreting' is explicit when-to-use advice. It does not explicitly name alternatives or when-not-to-use, but the 'no archive needed' framing implies differentiation from the archive-dependent siblings, giving clear context without formal exclusions.

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