set_helius_api_key

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

Annotations declare idempotentHint=true, readOnlyHint=false, destructiveHint=false. The description adds context: runtime-only memory, takes precedence over env var, rejects URLs to prevent prompt injection, and clarifies persistence. No contradictions.

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 front-loaded with the main action and well-organized, though somewhat lengthy. Every sentence adds value, but slight trimming could improve conciseness. Still very good.

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?

Despite no output schema, the description explains the effect (used for subsequent Solana calls until restart), security considerations, persistence, and agent behavior. Complete for a simple setter 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?

The single parameter 'apiKey' is fully described in both schema (coverage 100%) and in the description, which adds detail about UUID format, bare key requirement, and where to obtain it. The description enhances understanding beyond the schema.

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 the tool sets a Helius API key for Solana RPC reads at runtime without restart, constructs the canonical URL, and explains its precedence. This is a specific verb+resource that distinguishes it from sibling tools like set_demo_wallet or set_etherscan_api_key.

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 explicit when-to-use guidance: 'when the user pastes a key in chat...call this tool immediately.' It also tells where to get the key (Helius dashboard), what not to do (never echo the key), and offers an alternative for persistence across restarts (vaultpilot-mcp-setup).

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