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

The description discloses key behavioral traits: it's a free read (checking costs nothing), it returns different response shapes depending on credential type, and it explicitly notes that the graph/map meter debits this same wallet. Since no annotations are provided, the description carries the full burden, and it does well by explaining the read-only nature and the wallet relationship. It doesn't mention rate limits or error cases, but the core behavioral context is strong.

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 dense but well-structured, front-loading the key fact that it's a free read. It packs a lot of information into a few sentences, including credential types, endpoints, and return shapes. It's slightly long but every sentence earns its place. The parenthetical about the graph/map meter is useful context, though it could be trimmed.

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 tool has one optional parameter, no output schema, and no annotations, the description is quite complete. It explains the two credential paths, the return shapes, and the relationship to the graph/map meter. It doesn't describe error cases or what happens with invalid credentials, but for a simple balance check, the description covers what an agent needs to call it 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 description coverage is 0%, so the description must compensate. It does: it explains that wallet_id is not needed for GreenlandAI agent keys (reads own wallet) but is used for JoulePAI/ENYAL credentials. This adds meaning beyond the bare schema, which only shows wallet_id as an optional string with a default of null. The description could be more explicit about what happens if wallet_id is omitted for a JoulePAI credential, but it's largely sufficient.

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's purpose: checking a wallet balance. It specifies the verb ('reads', 'checks'), the resource (wallet balance), and distinguishes between two credential types (GreenlandAI agent key vs JoulePAI/ENYAL credential) with different behaviors. It also differentiates from siblings by noting this is the wallet check before calling the graph/map meter.

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 explicitly explains when to use this tool: to check your own wallet balance before calling the graph/map meter. It also explains the alternative paths based on credential type: a GreenlandAI agent key reads its own wallet with no wallet_id needed, while a JoulePAI/ENYAL credential reads by wallet_id. This is clear usage guidance with no ambiguity.

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