Store a provider API key in the caller's encrypted credential vault — the result of a conversational 'paste your key' step. Returns the stored credential's summary; the key itself is never echoed back.
| Name | Required | Description | Default |
|---|---|---|---|
| label | No | ||
| apiKey | Yes | The key to vault | |
| baseUrl | No | For providers that take a custom endpoint | |
| provider | Yes | Provider id, e.g. anthropic, openai, github |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It usefully discloses two traits that structured data does not: the key is stored encrypted and is never echoed back in the response. It still omits important mutation semantics such as overwrite/idempotency behavior and any auth or validation requirements.
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?
Two tight sentences, front-loaded with the action and the security-relevant return behavior. Every clause earns its place with no redundant restatement of the tool name.
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?
Because there is no output schema, the description rightly states what comes back (a credential summary, not the key). For a credential-writing tool with no annotations, though, it should also address re-provisioning/overwrite behavior and error conditions to be fully complete.
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 75% (label is undocumented), and the schema already explains apiKey, baseUrl, and provider. The description adds no parameter-level meaning beyond that, so the baseline of 3 is appropriate with the schema doing the heavy lifting.
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?
Specific verb (Store) plus a precise resource (a provider API key in the caller's encrypted credential vault). It is instantly distinguishable from all siblings, which deal exclusively with graphs, runs, and templates.
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 phrase "the result of a conversational 'paste your key' step" implies the context in which this tool fires, which is useful. However it gives no explicit when-to-use/when-not-to-use guidance, no prerequisites, and does not say whether calling it again for the same provider overwrites or creates a duplicate.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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