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

With no annotations, the description carries the load and does well: it discloses the data source (Fed via FRED/ALFRED), that revisions are explicitly flagged and 'never pose as print-day numbers', how surprise is computed (market-implied vs trend-model fallback), and the daily release cadence. It omits auth/rate-limit behavior beyond the x402 price note.

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 resource and scope, and the payoff (revisions, surprise, next release, mini-series) follows immediately. Slightly dense with a mild restatement of 'latest 10-year Treasury yield print' across the first two clauses, but no filler sentences.

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?

Without an output schema or annotations, the description must describe the return surface, and it does: latest print, revision flag semantics, surprise baseline, next release date, and a 12-observation series. Only minor gaps remain (no error/pagination or auth detail), which is sufficient for a fixed no-arg read.

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 takes zero parameters, so the baseline is 4. The description correctly adds no parameter information because none exists, and additionalProperties:false confirms a fixed no-arg call.

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?

States a specific resource ('10-year Treasury yield (Fed, daily)') and the exact payload contents: latest print, revisions, surprise. It also distinguishes itself from the generic sibling by noting it is the '/v1/econ/:series' shape 'bound to treasury-10y', so an agent can tell it apart from econ_series and econ_series_treasury-2y.

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 binding to treasury-10y plus 'daily' cadence makes the use context clear, and the reference to the generic /v1/econ/:series endpoint implies when this specialized variant applies. However, it never explicitly states when to prefer this over econ_series or the 2y sibling, so no exclusion guidance is given.

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