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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds behavior beyond that: ordering (newest first), the unit of change (per-close changes/invalidations), and the payload contents (new call plus a link). It says nothing about result volume or pagination, which is a minor gap for a list-style tool.

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?

One sentence plus one usage sentence, front-loaded with what is returned and the ordering. Every clause earns its place — the 'with the new call and a link' detail and the 'instead of re-reading every market' contrast both add information.

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 single-parameter read tool with rich annotations and no output schema, the description is nearly complete: it covers what is returned, ordering, and the intended workflow. The only shortfall is undefined return detail (what the link points to, how changes vs. invalidations are represented), which would matter slightly more given the absence of an output schema.

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% and the single `days` parameter is fully documented with default, minimum, and maximum, so the schema carries the burden. The description's phrase 'recent closes' aligns with `days` but adds no syntax or edge-case meaning (e.g., that days counts closes, not calendar days, or what happens at the 30 cap). Baseline 3 is appropriate.

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 names a specific resource and filter: markets whose Elliott Wave call was changed or invalidated at recent closes, returned newest first with the new call and a link. That is a clear verb+resource+scope, and the 'changed/invalidated' qualifier distinguishes it from the listing siblings (list_markets, get_market, search_markets). It stops short of naming an alternative tool, which keeps it from a 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?

It gives explicit when-to-use guidance: 'Use it to react only when a call moves instead of re-reading every market,' which implicitly routes the agent away from polling get_market/list_markets. The exclusion is phrased as a workflow preference rather than an explicit when-not-to-call rule, so it is clear context without a hard boundary.

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