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

Annotations declare non-read-only, idempotent, non-destructive, closed-world, but the description adds genuinely new behavior: the write does not alter the flag's current state until the timer fires, that setting a schedule overwrites any existing schedule (a side effect the destructiveHint=false hint does not convey), and the FLAG_NOT_FOUND failure mode. This is meaningful disclosure beyond the structured fields.

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?

Front-loaded with the core action and the semantics that follow, and most sentences carry non-obvious information. The 'Arguments:' sentence largely duplicates the schema and the get_integration_guide pointer is slightly tangential, so it is efficient but not maximally tight.

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?

For a 4-parameter mutation tool with no output schema, the description covers effect on current state, replacement semantics, error behavior, and an integration prerequisite — everything an agent needs to call it correctly without follow-up. Return-value detail is unnecessary since no output schema exists.

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 the schema already documents key, at, state and app. The description restates key/at/state and the enum values, adding only the 'by KEY' emphasis and format example already present in the schema, and it omits the optional app parameter entirely. Baseline 3 is appropriate when the schema carries the parameter detail.

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 verb (schedule), a specific resource (a future state transition on a feature flag) and the exact scope ('keeps its current state until the timestamp, then moves to the scheduled state'). It is immediately distinguishable from siblings like clear_flag_schedule, toggle_feature_flag and update_feature_flag 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?

Explicitly names the alternative for the inverse operation ('use clear_flag_schedule to remove it'), warns that a new schedule replaces an existing one, and prescribes a prerequisite ('call get_integration_guide with topic=feature-flags'). When-to-use, when-to-be-cautious, and the adjacent tool are all covered.

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