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

The description goes well beyond the annotations (readOnlyHint=false, destructiveHint=true): it discloses that the tool builds an unsigned transaction rather than moving value, that transactionBase64 is returned only after builder-side RPC simulation passes, that approval is conditional on safeToApprove/approvalBlocked flags, and that the hosted builder never receives keypair bytes with finalization required locally. These are substantive behavioral traits not captured by 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?

The core purpose is front-loaded in the first sentence, followed by the critical approval/simulation gates and the SAP execution guidance. The SAP MCP execution guidance block is boilerplate that also appears verbatim inside the input schema description, introducing some redundancy, but overall every sentence earns its place and the length is appropriate.

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 that an output schema exists (so return format is already documented), the description covers everything an agent needs to invoke correctly: what it builds, the simulation gate, the approval condition, the payment/estimation workflow, and the signer boundary. The only minor omission is explicit routing among near-identical close-variant siblings, which the name and enum already make self-evident.

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%: each of the four parameters (owner, priceUsd, percentage, principalToken) has a meaningful description in the schema itself, including the enum values XAU/XAG/WTI and the percentage default of 1000000. The description adds no parameter-level meaning beyond the schema, so the baseline of 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?

The description states a specific verb and resource: 'Build an unsigned transaction to close a long commodity position on Adrena.' This precisely distinguishes it from sibling tools like sap_adrena_build_close_commodity_short (short commodity), sap_adrena_build_close_long (non-commodity long), and sap_adrena_build_open_commodity_long (open vs close). The purpose is unambiguous.

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 provides clear operational context: when to show approval ('only when safeToApprove=true and approvalBlocked=false'), when not to finalize, and the routing/paid-builder flow ('call sap_estimate_tool_cost first, then use sap_payments_call_paid_tool if the runtime cannot handle x402 natively'). It does not, however, explicitly name sibling alternatives or state when to prefer this over close_commodity_short or close_long, so it stops short of a 5.

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