player_pack_purchases

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

With no annotations provided, the description correctly carries the full disclosure burden and does so exceptionally: it is a read operation, never purchases, issues a single logical GET, never auto-fetches continuation pages, truncates arrays at 100 rows/256 KiB with truncation reported, and refuses oversized records. This goes well beyond minimal safety disclosure and proactively manages agent expectations about network behavior and failure modes.

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 description is front-loaded with purpose, then proceeds through safety, network behavior, and failure modes in a logical order. A slight redundancy exists between 'never purchases packs' and the earlier read framing, but no sentence is wasted overall; the density is appropriate for a tool with no annotations.

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 only 2 parameters, no annotations, and no output schema, the tool description alone must deliver everything an agent needs for a safe call: purpose, read-only guarantee, single-request behavior, non-pagination, response-size limits, truncation reporting, and refusal policy. For a low-complexity tool this is complete; the only thing an agent cannot know is the exact field shape, which would normally come from an output schema.

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 0%, so the description must compensate. It adds meaning by explaining which inputs are required and why ('Required inputs reflect tool policy as well as measured upstream requirements'), noting pass-through filters, and warning that effectiveness of declared filters is 'not implied.' It establishes username as the player identifier and edition as the optional filter, though it does not explain edition values or formatting.

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 first sentence states a specific verb+resource: 'Read the upstream pack-purchase summary for one player and optional edition.' It is clearly a read-style summary tool for a single player, which differentiates it from the batch-purchase stats (purchase_stats), pack-data endpoint (cards_pack_data), and general player inventory tools in its siblings.

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 makes the intended use clear ('read ... summary for one player and optional edition') and reinforces that it 'never purchases packs,' which removes a natural misuse concern. However, it does not explicitly name alternatives or state when-not-to-use compared to the many sibling player_* and purchase_* endpoints, so it stops short of the 5-level.

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