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

Annotations cover the safety profile (readOnlyHint, openWorldHint=false), so the bar is lower, yet the description still adds meaningful operational context: it counts against a daily fair-use cap with concrete tier limits (200 Starter / 1,000 Pro), requires an API key, and constrains past dates to plan history. Those are exactly the non-obvious traits an agent needs before invoking.

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?

Dense, front-loaded and largely waste-free: output scope first, then defaults/dependencies, then cost and auth. Every sentence carries information, though the change-event list is somewhat enumerative and could compress.

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?

For a read-only aggregation tool with no output schema, the description is nearly complete: it defines the returned content, the default behavior, the date dependency, cost, and auth. The main gap is feed enumeration meaning, which no output schema exists to cover.

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 only 33% — just the date field is annotated. The description partially compensates by naming the window values (1d/7d/30d) and stating the date-requires-feed dependency, but it never explains what the six feed enum values select, so half the parameters remain semantically thin.

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?

It states a specific output: top movers by stars/likes/points across 1d/7d/30d plus named change-event types. That's concrete verb+resource. It does not, however, distinguish itself from near-neighbors like get_momentum_leaderboard or get_history, so an agent must guess which 'movers' tool is authoritative.

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?

It gives real usage constraints — 'Latest by default; past dates need feed and must be within your plan history' — which tell the agent how to call it. But it never says when to prefer this over get_history, get_momentum_leaderboard, or the per-feed getters, leaving alternative selection implied at best.

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