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

The description goes well beyond the annotations by explaining the signer boundary, local signing requirement, null-field behavior, paid-pricing model, and that hosted builders never receive keypair bytes. It also warns that value-moving results must be finalized locally, which is exactly the behavioral context an agent needs. No contradiction with annotations is present.

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 first sentence is excellent and front-loaded, and the text uses clear sections. However, the 'SAP MCP context' and 'SAP MCP execution guidance' blocks partially repeat the same intent and paid-builder/pricing information, making the description longer than necessary without adding proportionate new information.

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?

The description covers the safety model, signer policy, configured RPC, active SAP profile, pricing, routing, and null-field behavior — enough context for a complex paid builder tool. It could be more complete by explicitly stating that at least one replacement field is generally needed, since all parameters are technically optional in the 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 100%, so the baseline is 3, but the description adds meaningful semantics: null fields are ignored on-chain, ownerWallet is described as the sole required signer, and replacement fields like pricing and capabilities are full replacements rather than merges. The only ambiguity is that ownerWallet is called 'required' while the schema reports 0 required parameters.

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 opens with a specific, meaningful statement: 'Hosted-safe unsigned builder for update_agent.' This immediately identifies the verb (build), the resource (update_agent transaction), and the key behavioral mode (unsigned, hosted-safe). It does not explicitly distinguish itself from nearby sibling build tools like sap_build_agent_register_transaction, so it falls short of a 5.

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 substantial operational guidance: it is a paid builder, estimate first, finalize unsigned transactions locally, and call sap_estimate_tool_cost before paying. However, it never explicitly states when to choose this tool over alternatives such as sap_update_agent or other sap_build_agent_* tools, and it does not name exclusions or alternative routing conditions based on the user's actual goal.

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