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

Annotations only declare readOnlyHint, but the description adds substantial behavior: $0.05 per call, no re-payment for repeats via cursor, stable ids, and the fact that lang="en" returns entities without sentiment. Cost and idempotency disclosure go well beyond structured fields.

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?

Cost, scope and cursor behavior are front-loaded, and every clause carries information. It is a dense run-on sentence with stacked parentheticals, which slightly hurts readability but wastes little.

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?

No output schema, yet the description enumerates the returned fields (id, entities, sentiment, next cursor) and the pricing model, which is exactly what an agent needs to decide and call correctly. Nothing material is missing.

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 coverage is 100%, so baseline is 3, but the description adds real meaning: it explains lang="en" yields entities only with no sentiment score, a consequence not stated in the schema. The since parameter's cursor semantics are also clarified as an anti-double-billing mechanism.

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+resource: a cursor-based feed of Indonesian articles newer than a given timestamp, returning id, entities, sentiment and next cursor. That is clearly distinguishable from a report or headline tool, though it never names which sibling (e.g. indonesia_new_since) it supersedes.

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?

Explicitly frames the use case: polling agents using ?since so they 'never re-pays for repeats', plus a note on when to pass lang="en". It gives clear context but no exclusions or comparison to the near-identical siblings like indonesia_new_since.

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