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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds value beyond that: the output carries units in millions and trillions, official IDs, adjustment bases, release quarter, hashes, and attribution, plus an explicit caveat about comparing levels across differing definitions. It does not state behavior on unknown slugs or ordering of results.

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?

Front-loaded with the core action and scope, followed by the payload contents and usage triggers. It is dense but every sentence carries information; the enumeration of output fields is the only mild padding, though it compensates for the absent output schema.

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 usefully enumerates what is returned (values in two units, official IDs, adjustment bases, release quarter, hashes, attribution) and gives use cases plus a definitions caveat. It is nearly complete for an agent to call it correctly, lacking only edge-case behavior (invalid slug handling, multi-series alignment) to reach a 5.

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 both parameters are already documented (series as 'one to eight unique exact curated slugs or official series IDs', response_format enum). The description only restates the one-to-eight cardinality and the curated-aggregate framing, adding no new syntax or format guidance. Baseline 3 is appropriate when the schema does the heavy lifting.

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 and resource: 'Return the latest hosted quarter for one to eight curated Federal Reserve Z.1 balance-sheet or debt aggregates on one consistent release.' The phrase 'latest hosted quarter' and 'one consistent release' implicitly distinguishes this snapshot from the historical/change-oriented siblings (fed_z1_series, fed_z1_change, fed_z1_catalog), but none of those siblings are named explicitly.

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?

It gives concrete trigger phrases ('latest household net worth and liabilities', 'compare current household, business, and federal debt levels') and positions itself 'as a macro evidence leg alongside FRED and Treasury tools,' which tells the agent when to compose it with others. It adds a caution ('Do not compare levels without considering definitions and adjustment bases') but stops short of naming which sibling to use for history or deltas.

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