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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely non-obvious traits: unit conventions (percent for YTM, basis points for spreads, prices per 100 face), hard caps of 730 days and 750 returned points, and a 1 read-unit billing cost for history. Missing: whether exceeding the caps errors or truncates, and any rate-limit/auth context.

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?

Three compact sentences: capability first, unit conventions second, caps and billing last — no filler. The units sentence is slightly boilerplate for a country-risk tool since bond prices per 100 face are not obviously part of this return value, which costs a point.

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?

Annotations cover safety and an output schema presumably covers the return shape, so omission of return details is fine. For a 4-param tool with 0% schema coverage and optional date filters, though, the description leaves the core parameter mechanics (range vs. explicit dates) unexplained, which is a gap an agent will notice when constructing a history call.

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 0%, so the description carries the full burden, yet it never explains the `range` enum (1w/1m/3m/ytd/1y/2y), the date format for `start`/`end`, whether explicit dates override `range`, or the default of `include_history`. Only the 730-day/750-point history cap indirectly informs `start`/`end` usage, leaving most of the four parameters undocumented.

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 verb and resource — 'Return the current Argentina country-risk spread and deltas' — with the optional history mode named up front. It does not distinguish itself from plausible siblings such as bondterminal_get_history or bondterminal_treasury_curve, so an agent must infer the boundary rather than read it.

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?

'With optional history' plus the billing sentence ('current snapshot is free; including history costs 1 read unit') gives a real decision cost that guides whether to set include_history. However, there is no explicit statement of when to prefer this over bondterminal_get_history or bondterminal_treasury_curve, and no note on how range/start/end interact for history requests.

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