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

Annotations already declare readOnly/idempotent/non-destructive, so the safety bar is low, and the description adds real behavioral context: results are pinned to 'the latest published block' and the response echoes back the date actually served, which matters for a time-series tool. It still doesn't say whether it fails when no block is published or how staleness is signalled.

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?

Two compact sentences: the primary statement leads, then the REST mapping. No filler. The dense jargon ('URPD', 'price-grid rounding') assumes vocabulary the description never defines, which is a minor readability cost.

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?

An output schema exists so return values need no explanation, and the description covers scope (latest block) plus the date echo. Its key deficiency is deferring field/unit semantics to a different endpoint's documentation, which an agent may not have loaded — the completeness depends on that cross-reference being resolvable.

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 67% but the enum $defs for cohort, weight and agg are extensively documented, and the description points to `GET /api/urpd/{cohort}/{point}` as the reference for units, price-grid rounding and weighting semantics — which ties directly to the `agg`/`weight` params. It adds a pointer rather than full parameter meaning, so it's above baseline but not self-sufficient.

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 the resource (URPD) and the scope qualifier (latest published block), and the REST mapping `GET /api/urpd/{cohort}` makes the underlying operation unambiguous. It implicitly distinguishes itself from the sibling `get_urpd` (historical) via 'latest', but never names that sibling explicitly.

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?

Usage is only implied: the word 'latest' tells an agent this is the no-date variant, but the description never says 'use this instead of get_urpd when you want the most recent snapshot', nor does it state prerequisites or when not to use it. An agent must infer the routing decision from a single adjective.

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