Save the user's ElevenLabs API key

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

Description adds significant behavioral context beyond annotations: writes to specific file with restricted permissions, never leaves the machine, idempotent behavior confirmed by noting calling with no args just checks status. No contradictions with 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?

Description is reasonably concise given the detail needed. Front-loaded with primary action, then usage conditions, security, alternatives. Each sentence serves a purpose, though slightly lengthy.

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?

Complete for a key-setter tool: explains security, alternative config, and status-check behavior. No output schema needed as side-effect is clear. Sibling tools (like generate_voiceover) likely depend on this key, making context sufficient.

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 already covers the single optional parameter (api_key) with description 'omit to only check current status'. Description restates this but doesn't add new semantic meaning beyond the schema. Baseline 3 for high coverage.

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?

Clearly states the tool saves the user's ElevenLabs API key for generating voiceovers. Distinguishes itself from sibling tools by being the only one handling API key configuration.

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?

Provides explicit when-to-call: only when a tool reports no key or user offers one. Instructs to ask user and never invent. Offers alternative environment variable setup, giving complete usage guidance.

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