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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds genuinely useful scope disclosure: the exclusions (no walls, gamma flip, net GEX, spot) tell the agent this is a narrow content window rather than a full snapshot. It does not mention pagination or response ordering, but the content-boundary disclosure is the valuable part.

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 and front-loaded: the scope is stated first, exclusions second, and the parameter constraint last. It is written as a verbless fragment, which is slightly awkward, but every clause carries 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?

With no output schema, the description steps in to say the return is a list of regime segments with start and end times, which is what an agent needs to consume the result. Nothing important is missing for a simple one-parameter read tool.

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% and the schema already gives the pattern and the 'replay date catalog' constraint, so the baseline is 3. The description only restates the YYYY-MM-DD format and adds that it is one date per call, which is largely implied by the single-property schema.

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 resource (regime segments for one past trading day) and explicitly scopes it against richer siblings by ruling out walls, gamma flip, net GEX and spot. An agent can distinguish this from get_regime or get_market_structure without opening any 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?

Frames the call as the 'compact replay' for when only the regime change tape is wanted, and states the one-date-per-call constraint. It never names the alternative tool (e.g. get_regime) that would be used when the excluded fields are needed, so selection is implied rather than explicit.

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