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

With no annotations present, the description carries the full burden and discharges it well: it discloses the KV-read vs database-read behavior, that the schedule is a compiled-in default unless a validated override exists, that the KV count is eventually consistent so tier boundaries can drift, and precise freshness semantics (observed_at, valid_until, stale_if_error). This is exactly the kind of operational context annotations would otherwise provide.

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?

Purpose is front-loaded and most sentences carry real signal (counting rule, consistency note, freshness). Minor waste exists: the leading 'Spec 097 / ADR-035 Amendment C8' citation is opaque noise for an agent, and the receipt sentence partly duplicates the schema. Overall efficient but not zero-waste.

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?

No output schema and no annotations, yet the description fully describes the return shape (rows of tier/from/to/price_atomic), the schedule_source and schedule_hash semantics, the band floor/ceiling, and the freshness fields. Nothing an agent needs to interpret or trust the payload is missing.

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% for the single `receipt` parameter, so the schema already explains its behavior and additive/failure semantics. The description's line 'Add `?receipt=true`' only restates the same idea in query-param syntax, adding little beyond the schema. Baseline 3 per the high-coverage rule 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?

Opens with a specific verb+resource: 'Returns the usage-tiered price schedule for paid calls.' This is unmistakably distinct from siblings like get_stats, get_freshness, or get_subscription, and it even scopes the audience (paid calls). An agent can place it immediately.

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 — an agent infers you call this to learn prices before making paid calls, but the description never says when to use it, when not to, or which sibling (e.g. get_subscription) is the alternative. It also doesn't state prerequisites such as whether an API key is needed to read the schedule.

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