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

With no annotations, the description carries the full burden and adds useful behavioral context: it explains that it never returns private keys (a security guarantee) and describes what it returns (Flux ID, payment address, balance, USD value, configuration help). It doesn't cover whether the operation is read-only or any rate limits, but the explicit key-safety statement is a strong plus.

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 two sentences, front-loaded with the return values and then a key safety note. Every sentence earns its place without redundancy.

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 (2 optional parameters, no output schema, no annotations), the description is fairly complete. It explains what is returned and a critical safety behavior. It could be improved with a note on when to use this tool or the read-only nature, but it covers the essentials adequately.

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 100%, so the schema fully documents both parameters, including their purpose and security warnings. The description does not add any parameter semantics beyond what the schema provides, so the baseline of 3 is appropriate.

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 states a specific verb (returns) and resource (Flux ID, payment address, spendable FLUX balance with USD value), making the tool's purpose clear. However, it does not differentiate this identity/balance check from siblings like flux_get_network_info or flux_generate_keys, which might also relate to keys or addresses.

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?

There is no explicit guidance on when to use this tool versus alternatives. It does not mention conditions like 'use this to check your balance before deploying' or 'only after configuring keys', leaving the agent to infer the context from the title and description alone.

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