ebay_get_seller_funds_summary

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

Goes well beyond readOnlyHint=true by disclosing the required OAuth scope, the Digital Signature requirement for EU/UK sellers with the exact env vars to set (EBAY_SIGNING_KEY_JWE, EBAY_SIGNING_PRIVATE_KEY), and the empty-result contract. These are non-obvious failure modes an agent could not infer from annotations or schema.

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?

Three sentences ordered by importance: what is returned, edge-case response, then auth prerequisites. No filler; even the env var names earn their place as actionable setup detail.

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?

For a single-optional-param read-only endpoint with no output schema, the description supplies the return shape, the empty case, and the auth prerequisites — everything needed to call it and correctly interpret results.

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?

Only one optional parameter and schema coverage is 100%, so the schema fully documents marketplaceId, its header override behavior, and the EBAY_US default. The description adds nothing about the parameter, so 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 the seller's funds not yet paid out') and enumerates the breakdown returned: available, processing, on-hold, total. The 'not yet paid out' framing implicitly separates it from payout-oriented siblings (ebay_get_payout_summary, ebay_get_payouts), though no sibling is named explicitly.

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?

Gives clear operating context: requires the sell.finances scope, and returns success with no data when nothing is pending, which tells the agent how to interpret an apparently empty response. It stops short of explicitly naming an alternative summary tool to use when payouts rather than pending funds are wanted.

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