ebay_get_transaction_summary

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

Goes well beyond the readOnlyHint annotation: it names the required OAuth scope, discloses that eBay demands Digital Signatures on Finances calls for EU/UK sellers, and tells the agent which environment variables (EBAY_SIGNING_KEY_JWE, EBAY_SIGNING_PRIVATE_KEY) must be set. That is exactly the kind of failure-mode context an agent cannot get from structured fields.

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?

Four sentences, purpose front-loaded, then constraint, then auth, then signing caveat — a sensible descending order of importance. The signing sentence is long but every clause is actionable; only the redundant transactionStatus example slightly duplicates the schema.

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 only two parameters, no output schema, and simple annotations, the description covers purpose, required scope, filter constraint, and the EU/UK signing prerequisite. It stops short of describing how results are bucketed or aggregated, which would help an agent interpret the response.

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 filter description already enumerates every criterion and format, so the schema carries the load. The description's restatement of the transactionStatus requirement plus the example adds emphasis but no new meaning, so the baseline 3 applies.

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 and resource ("Get cumulative transaction counts and amounts from the eBay Finances API") plus a scope detail ("including on-hold payments"). The word "cumulative" implicitly separates it from ebay_get_transactions and ebay_get_payout_summary, but no sibling is named outright.

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 hard prerequisites (sell.finances scope, mandatory transactionStatus criterion) that imply when the call is valid, but it never says when to prefer this aggregate summary over ebay_get_transactions, ebay_get_seller_funds_summary, or ebay_get_order_earnings_summary. Usage is inferred rather than stated.

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