Update SAP Agent With Local Signer

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

Annotations indicate this is a write operation (readOnlyHint=false) and not destructive (destructiveHint=false). The description adds critical behavioral context: 'OOBE never receives keypair bytes' and 'no hosted x402 fee is charged', indicating security and cost implications. It also states the update is local and non-custodial. However, it doesn't fully clarify whether update replaces or merges fields (schema suggests full replacement for arrays like pricing, but description says 'updates' which could be ambiguous). Still, it provides substantial value beyond annotations.

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 description is a single paragraph of concise, front-loaded sentences. The first two sentences state the purpose and usage condition. Subsequent sentences detail what is updated and key behavioral notes. Every sentence adds value without redundancy, making it efficient for an agent to parse.

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 the tool's complexity (11 parameters, output schema exists), the description covers the trigger condition, update scope, security, and confirmation requirement. It does not describe the return value, but the output schema handles that. Missing: what happens if confirm is false or if the transaction fails? Nevertheless, the description provides sufficient context for an agent to decide when and how to invoke this tool.

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%, so the baseline is 3. The tool description adds meaning beyond the schema by explaining the context for certain parameters: 'metadataUri' is an alias for 'agentUri' and warns against using desktop file paths; 'confirm' must be true; 'pricing' and 'capabilities' are full replacement arrays. These additions help the agent understand parameter usage, justifying a score of 4.

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 clearly states it updates a SAP agent with a local signer, specifically for hosted users when the hosted update returns 'hosted_local_signer_required'. It enumerates the updatable fields (name, description, capabilities, protocols, pricing, agentUri/metadataUri, x402Endpoint), distinguishing it from the hosted counterpart (sap_update_agent). The verb 'update' combined with 'local signer' and resource 'SAP agent' provides a specific purpose.

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?

Explicitly tells when to use this tool: 'Use this when hosted sap_update_agent returns hosted_local_signer_required.' This directly contrasts with the hosted sibling tool and provides a clear condition. It also implies not to use it otherwise, offering strong usage guidance.

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