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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered; the description adds genuinely new behavioral context: venue links are 'plain unpaid links checked nightly', scores_30d is a downsampled tick feed with explicit cadences, and driver/reason are null when no event is open. It omits auth, rate limits and pagination, so not a 5.

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?

It is front-loaded correctly with the 'Use when' trigger, and most clauses carry load-bearing information. But it reads as one dense wall of run-on sentences with the schema-shaped detail (sampling cadence, deprecated aliases) interleaved, which makes it harder to scan than it needs to be.

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 correctly shoulders the burden of describing the return payload, including edge cases (null driver), field equivalences (latest.score = last scores_30d point), and a deprecation horizon for heat_7d/peak_heat. Coverage of error conditions and response envelope is missing, keeping it at 4.

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 symbol parameter, so the schema already carries the semantics. The description only implies the domain (crypto and stocks both accepted) without adding format or constraint detail, so the 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?

The description states a specific verb and resource with unusual precision: 'One asset in depth: latest snapshot, scores_30d, the open event and the 10 most recent past events ... and venues.' An agent can tell exactly what it retrieves. It stops short of naming a sibling tool to distinguish itself from, so it lands at 4 rather than 5.

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?

'Use when someone asks about one coin or stock' followed by concrete triggers ('why $X is moving', 'whether its volume is unusual', 'how its past spikes turned out') gives clear selection context. There is no explicit when-not-to-use clause and no alternative tool named, which keeps it below 5.

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