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

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so the safety profile is covered. The description does add genuinely useful behavior context the annotations cannot convey: driver is null when no event is open, score equals the last scores_30d point, and links are 'plain unpaid... checked nightly against each venue's product list'. That is meaningful, but it drifts into return-value documentation with no output schema, so it is not a clean disclosure of operational traits.

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?

A single run-on block of roughly 180 words with no paragraph or bullet structure, mixing usage triggers, response anatomy, deprecation policy, and an API cross-reference. The key differentiator is front-loaded, but the remainder is dense and hard to scan, so sentences do not obviously earn their place individually.

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 one-parameter read tool with no output schema, the description compensates by describing the returned shape and the no-open-event null behavior, and it pre-loads the deprecation timeline for heat_7d/peak_heat. But it omits pagination or size bounds for '10 most recent past events', and the REST endpoint reference is a distraction rather than necessary context.

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% (symbol, with a 'e.g. BTC or GME' example), so the schema carries parameter meaning. The description's only parameter-adjacent signal is the mention of 'GET /api/asset/{symbol}', which adds no new semantics beyond the schema's ticker definition. 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 specific verb and resource ('One asset in depth') and enumerates the returned artifact set (snapshot, scores_30d, events, venues). The opening 'Use when someone asks about one coin or stock' distinguishes it from the index/board siblings, so the agent can route 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 concrete triggering questions ('why $X is moving', 'whether its volume is unusual') that map cleanly to this tool rather than arena or board. However, it never names a sibling alternative or an exclusion, so the when-not is inferred rather than stated.

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