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

Annotations already declare readOnlyHint=true, so the safety profile is established. The description adds behavioral context beyond that: 'Free discovery' signals no cost/side effects, and the sequencing instruction ('before querying a new pack') is a valuable ordering constraint. No contradictions 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?

Two sentences, no wasted words. The opening 'Free discovery' immediately signals the tool's nature, and the rest packs specific value (metadata, coverage, freshness, guidance, examples) into a structured list. Every sentence earns its place.

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 one simple parameter, a readOnly annotation, and no output schema, the description does enough: it lists the categories of returned information and tells when to call. The only minor gap is precise output format details, but the description covers the essential context for invoking the tool correctly.

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% for the single parameter pack_id, which already states it is a 'Pack identifier from get_catalog.' The description reinforces this by referring to 'one pack' and 'new pack,' but adds no semantic detail about the parameter beyond what the schema provides. Baseline 3 is appropriate.

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 states a specific verb ('Returns') and resource ('one pack'), and enumerates the contents: metadata, coverage, freshness, canonical tool guidance, and first-query examples. It clearly differentiates from siblings by focusing on a single pack's details, unlike get_catalog which likely lists packs.

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 gives explicit usage guidance: 'Call this before querying a new pack so you can see time shape, coverage limits, and the paste-ready first query.' This is clear when-to-use context. It doesn't explicitly mention when not to use or name alternative tools, so it misses the top tier.

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