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

Annotations already cover read-only, idempotent, closed-world, non-destructive behavior, so the bar is lower; the description then adds non-trivial output semantics — per-currency grouping, per-account figures with date and source, and a flag that stale figures are named. That staleness disclosure is behavior an agent would otherwise not know since there is no output schema.

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?

One dense sentence with no filler, and the core definition is front-loaded. The trailing clause 'old figures named' is cryptic jargon that costs a little clarity, but nothing is wasted.

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?

For a simple read-only, single-optional-param tool this is close to sufficient, and it usefully sketches return contents in the absence of an output schema. However, 'old figures named' is never explained (no staleness threshold), and it doesn't say how accounts are classified as held vs owed or how currencies are handled.

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% and the single as_of parameter is fully documented with default and ISO format, so baseline is 3. The description's 'on a day' restates the schema rather than adding syntax or edge-case meaning.

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 defines the computation precisely ('what is held less what is owed, per currency, on a day') and enumerates the per-account output (figure, date, source), which is far more specific than the bare title 'Net worth'. It lacks an explicit verb and never names a sibling, but no other tool in the large sibling list computes net worth, so it is distinguishable by topic.

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 statement of when to use this over purch_accounts, purch_payables, or purch_spend, and no prerequisites or exclusions. Usage is only implied by the word 'per currency'.

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