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

With no annotations provided, the description carries the full behavioral burden and does so well: it declares read-only semantics, names the underlying feed configuration, specifies the returned object fields, and discloses both test_mode behavior and automatic mock fallback when the feed is unreachable. This is strong transparency beyond the 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?

The description is three sentences with no wasted words. It front-loads the core purpose, states usage context, and then covers behavior and fallback mechanics efficiently. Every sentence adds distinct value.

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?

Despite having no output schema, the description explicitly lists the return fields {title, pubDate, link, summary, source}, making the tool's output predictable. It also covers configuration, filtering context via schema, test mode, and failure fallback, so an agent has enough context to select and invoke the tool correctly.

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 the schema already documents all parameters (limit, since, topic, test_mode). The description adds little parameter-specific meaning beyond mentioning `limit` and test_mode, but because the schema handles parameter semantics fully, a baseline 3 is appropriate.

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 opens with 'MT Newswires commodity headlines (read-only)' and immediately specifies the tool's action: pulling a configured RSS or JSON feed and parsing news items. It clearly identifies the resource (MT Newswires feeds) and output shape, and distinguishes it from sibling price/signal/portfolio tools as a commodity-news ticker.

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 description explicitly states 'Use as a low-latency news ticker for commodity-trader agents,' giving clear context for when this tool is appropriate. It does not explicitly name alternatives or state when not to use it, but its news-feed purpose is distinct enough among siblings that the usage guidance is reasonably complete.

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