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

Annotations declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety is well covered. The description adds meaningful behavioral context beyond those annotations: confidence bands WIDEN with horizon, it is a linear trend extrapolation 'NOT a guarantee', it requires >=3 daily snapshots, and it returns a caveat field. This is exactly the kind of limitation disclosure that helps an agent trust and interpret the result.

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?

The description is information-dense but well organized: purpose, behavior, use-cases, params, return shape, and exclusions each take one compact clause or sentence. The HONEST warning and Do NOT directives are clearly delimited and front-loaded after the core purpose. Nothing feels redundant with the schema.

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?

Given the output schema exists to document the return shape, the description appropriately covers what remains: when to use it, what it projects, its caveats, data-source ownership, and its prerequisites. The only minor omission is a concrete time span for the 'short history' caveat, but the >=3 snapshots requirement and widening bands make the behavior sufficiently clear.

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%, so both parameters are already documented in the schema. The description adds value by reinforcing that valid market_slug values come from rank_markets / get_market_dcpi_rank and that horizon_quarters=2 means ~6 months, which aids agent interpretation. This slightly exceeds the baseline for full schema coverage.

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 opens with a specific verb ('Forecast'), a precise resource ('a DCPI market's near-term trajectory'), and a concrete horizon (next 1-8 quarters). It names the projected quantities (excess_power_score, constraint_score), cites the data source, and explicitly distinguishes itself from get_market_dcpi_rank and rank_markets.

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?

Provides explicit when-to-use examples ('is this market trending toward BUILD or AVOID?', 'will Dallas power stay tight...'), explicit exclusions ('Do NOT use for a single point-in-time verdict', 'Do NOT use to rank many markets'), and names the alternative tools. It also documents the data requirement: needs >=3 daily snapshots or it declines.

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