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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, but the description adds substantial behavioral context: values are computed from real GL rows, never asserted, read live, and the tool is always free. It also explains the defect nature of unbalancedEntries and that solvent requires both conditions, going well beyond the structured 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?

The description is well-structured and front-loaded with the core question and answer. It is slightly longer than strictly necessary due to repeated CO references and the example call, but every sentence contributes meaningful context about behavior, output, or usage.

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?

With no output schema, the description fully compensates by listing all return fields and their meanings, explaining the solvency condition, and describing the data source and safety profile. It is complete for a parameterless read-only tool and fits well within the large sibling toolset.

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 tool has zero parameters and schema description coverage is 100%, so the baseline is 4. The description reinforces this by providing an example call with arguments {} and by explaining what each returned field means, which is the relevant semantic content for this parameterless tool.

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: it returns the dollar ledger's live solvency invariant for the Com float, including reserve, outstanding, margin, and unbalancedEntries. It distinguishes itself from siblings by naming its unique invariant and referencing the same 'verify, don't trust' posture as federation_latency and federation_pricesheet.

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 gives clear context for when to use the tool: to check whether the Com float is actually backed, and it notes that this is public, read-only, and always free. It does not explicitly name alternative tools to use instead, but the use case is unambiguous and the sibling differentiation is implied through the unique solvency invariant.

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