Update credential

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

Discloses significant behavioral traits: 'potentially breaking dependent workflows' warns of destructive impact, and 'isPartialData=false replaces the saved field set, while true requests a partial merge' explains update semantics. Also notes 'returns metadata without secret values,' informing about output privacy. These align with destructiveHint=true and readOnlyHint=false 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?

Four dense sentences pack all key information—purpose, risk, selection, partial semantics, type change, alternative, permissions, and return behavior—without redundancy. Semicolons effectively group related clauses.

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 tool's destructive potential, update semantics, permissions, secret handling, and the creation alternative. With an output schema present, not detailing return fields is acceptable; all essential usage aspects are addressed.

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?

Even with 100% schema coverage, the description adds meaning: it clarifies that credentialId selects the record, fields can be omitted to keep current values, type changes require data matching n8n_credentials_schema, and isPartialData toggles replace vs. merge. This goes beyond the schema's per-field descriptions.

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?

Description opens with 'Update one stored credential,' specifying verb and resource. It differentiates from create by noting 'Use create for a new credential,' and from other credential tools by focusing on the update action.

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?

Clear context: targets an existing credential selected by credentialId, with explicit alternative 'Use create for a new credential' preventing confusion with creation. Prerequisites (write/unsafe mode + update permission) and partial-update guidance help the agent decide when to invoke.

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