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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's real contribution is the data-availability caveat: no exit dates are kept, stock cannot be backfilled, and the series grows one point per day. That is valuable non-obvious context, though it says nothing about the limit/pagination behavior.

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 short paragraphs, front-loaded with the resource and filters, followed only by the caveats that materially affect interpretation. Every sentence earns its place.

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 not be described, and the temporal caveat is handled thoroughly. The gaps are the undocumented limit and area_type parameters against 0% schema coverage, which leaves the definition slightly short for a 7-parameter 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 description coverage is 0%, so the description must carry the burden. It clarifies that start/end are YYYY-MM-DD dates and that the series is sliced by area, channel and bedroom band, but leaves limit (default 90 points) and area_type granularity completely unexplained, so several parameters remain opaque.

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 and scope: a daily stock-on-market series for one area, channel and bedroom band, naming the exact measures returned (median age of dated live stock, median asking price/rent, new-build count). This distinguishes it from sibling series tools such as asking_price_index_series or market_volume_series without needing the 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 clear context for legitimate use: the series starts 2026-09-05 and a short series is expected rather than missing data, which pre-empts a common misreading. It does not name alternative tools or state explicit exclusions, so it stops short of a 5.

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