add_custom_token

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

With no annotations, the description carries full burden and discloses that token data is public on-chain with no secrets or keychain involvement, reassuring about safety and side effects. It also implies the operation is additive (no destruction).

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 well-structured paragraph that efficiently covers purpose, usage, privacy, and all inputs without redundancy. Every sentence adds value, and it is appropriately front-loaded with the core action.

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 complexity (5 required params, no output schema), the description thoroughly explains the tool's purpose, when to use, each parameter with examples, and security context. It is complete for an agent to select and invoke correctly.

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 coverage is 100% with descriptive parameter names and constraints. The description adds extra context like typical decimal values (18, 6) and clarifies contract address is public, enhancing 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 it adds a project-specific ERC-20 token to a MetaMask tracked-tokens list, distinguishes from default tokens, and gives concrete use-case examples like 'track ARB token'. It differentiates from sibling tools (list_custom_tokens, remove_custom_token).

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 states 'Use when the user asks: ...' and implies common tokens are already tracked, so not for those. Provides scenarios and contrasts with default tracked tokens, giving clear when-to-use and when-not-to-use guidance.

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