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

Annotations only supply readOnlyHint and openWorldHint, so the description carries most of the load and does it well: it discloses the scale semantics (50 = steady, >50 accelerating), the underlying sources, the provenance split (GDELT backfill from 2015 vs. live Tavily series from 2026-07-08), and the hourly refresh cadence. One tension: openWorldHint=false sits awkwardly with a tool that runs live external news searches, though it is not a hard contradiction since the query set is fixed to four topics.

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 return value and scale, then usage, then provenance/cadence, so an agent can stop reading early. Dense but not padded; the only cost is that the middle sentence packing four field names and the comparison logic is heavy.

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?

With no output schema, the description enumerates the returned fields (news_velocity, articles_24h, articles_72h_avg, topic_counts) and explains the index's interpretation, freshness, and historical coverage. Minor gap: it does not explain how per-topic topic_counts are keyed or whether values are cumulative vs. rolling.

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% for the single 'days' parameter, and the description never mentions it, so the schema does all the work. The only added context is the Gold-tier gating for history, which the schema already states; baseline 3 applies.

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 concrete verb and resource ('Returns a 0-100 US financial-news velocity index') plus the exact construction: four Tavily topic searches compared against a rolling average of prior runs. It also carves out its own scope with 'Velocity only, no sentiment or tone,' which lets an agent separate it from any sentiment/tone sibling without opening a schema.

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?

Gives three explicit invocation triggers: news flow spiking/quieting questions, timing event-driven volatility alerts, and headline-risk checks. The 'Velocity only, no sentiment' line doubles as an exclusion, but no alternative tool is named for the sentiment case, so the routing guidance is strong rather than complete.

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