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

Annotations already declare readOnlyHint=true and openWorldHint=true; the description adds the useful side effect that buying a pack auto-assigns an upgrade tier, plus what the tool returns (prices, stock, today's limits). It doesn't discuss rate limits or data freshness, but added context is solid.

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 compact sentences, front-loaded with read-only and identity. Minor redundancy between title and description but no wasted clauses.

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?

Single optional param, no output schema, annotations cover safety. Description covers what is returned, optional filtering, and the downstream effect of purchases; sufficient for correct invocation.

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% and the sole parameter is documented, so the baseline is 3. The description adds the semantic ('how much that Base address may still buy today') that the schema only partially captures.

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?

States a specific verb (read/list) and resource (GEODE upgrade packs sold for USDC on Base), names the concrete SKUs (Pebble, Diamond) and the seller. It is clearly distinct from siblings like geode_upgrade_build/prepare/status, which deal with paid upgrades rather than pack inventory.

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 buyer parameter's purpose is explained ('see how much that Base address may still buy today') and a side effect is noted, but there is no explicit when-to-use vs. geode_upgrade_status/prepare or when-not guidance.

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