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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so safety is covered. The description adds genuinely new context beyond them: no API key is required (an auth/access trait annotations do not express) and a hint at the output shape ('one compact line'). It stops short of describing response structure in depth, but for a read-only sample that is a reasonable level.

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 short sentences, zero filler, with the core value proposition (free, no key) and the format hint front-loaded and easy to scan. Every sentence carries information the schema and annotations do not.

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?

There is no output schema, so the description has to carry return-value information, and it does: it enumerates the instruments covered and describes the text output as one compact line. The json variant's shape remains unspecified, which is the one remaining gap for a tool with no output schema.

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 burden is on the description, and it only half-compensates: it explains what format=text produces but says nothing about what format=json returns or why one would choose it. The enum values and default are self-evident from the schema, so the added meaning is real but partial.

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 and scope: a free headline sample of the latest brief, with the exact content covered (2Y/10Y, 2s10s, curve shape, EURUSD/USDJPY, BTC/ETH). It implicitly separates itself from get_latest_brief by being a 'sample' rather than the full brief, but it never names that sibling, so the differentiation is inferential rather than explicit.

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?

'Open, no API key needed' plus 'Free' strongly implies the use case (quick, unauthenticated peek without credentials), which is real guidance. However, it never explicitly states when to prefer this over get_latest_brief or get_brief_by_date, leaving the agent to infer the routing from the word 'sample'.

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