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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds that it is 'Free discovery' and enumerates the returned content types, which exceeds the bare annotation. However, it does not disclose any pagination, limit, or error behavior, though those are less critical for a metadata lookup. The description adds value without contradicting 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?

Two sentences, no filler. The first sentence opens with a benefit ('Free discovery') and immediately states the output, followed by the usage trigger and the concrete outcomes. Every clause earns its place, and the critical guidance is front-loaded.

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 a single parameter, full schema coverage, and readOnly safety annotation, the description covers the essential context: what it returns, when to call it, and what to expect. It omits a formal response schema or error cases, but for a lightweight discovery tool these are not significant gaps. The mention of 'preferred canonical tool guidance' effectively routes the agent to correct subsequent actions.

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 provides a 100% descriptive parameter definition: 'Pack identifier from get_catalog. Newly catalog-admitted packs require no MCP schema change.' The description adds no further semantic detail about pack_id beyond what is already in the schema. Per the rubric, a baseline of 3 applies when schema coverage is high, and the description does not raise it further.

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 purpose: it returns detailed metadata, coverage, freshness, tool guidance, and first-query examples for one pack. It defines the resource as 'one pack' and the action as 'returns', which effectively distinguishes it from get_catalog (which lists packs) and query_dataset (which executes queries). The reuse of 'preferred canonical tool guidance' reinforces its role as a decision aid.

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 explicitly instructs 'Call this before querying a new pack', providing a clear when-to-use condition. It also explains the benefits (time shape, coverage limits, paste-ready query), which signals how it fits into the workflow. It does not explicitly state when to use alternatives like get_catalog or query_dataset, but the purpose differentiation is strong enough to imply the alternatives.

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