Read a Roblox FastFlag value (sUNC getfflag)

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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, so the safety profile is covered; the description goes beyond them by disclosing that the call is type-guarded and pcall-wrapped, the exact error object when getfflag is absent, and that unknown flags return nil. The cost/phase metadata adds further context, though the closing 'inspect tool-schema' line is boilerplate.

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 core purpose and error behavior are front-loaded and useful, but the 'Phase/cost/idempotency/Safety' block partially duplicates the annotations (read-only, idempotent) and the final 'On failure: inspect tool-schema...' sentence is generic filler that does not earn 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?

With no output schema, the description correctly supplies the return shape ({ name, value } or { error }) and the missing-dependency failure mode, plus prerequisites. It is nearly complete for a 3-param read tool; only per-parameter semantics for threadContext/timeoutMs lean entirely on the schema.

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 baseline is 3: the schema already documents name, timeoutMs, and threadContext including defaults. The description only restates the signature and gives one example flag name, adding little beyond structured fields.

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+resource ('Read the current value of a Roblox engine FastFlag by name') and how it is obtained (executor's getfflag(name)). The scoping detail — FastFlags are runtime feature toggles read at startup — makes it clearly separable from the sibling set-fast-flag and from generic value reads like read-path-value.

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?

Preconditions are stated ('Requires getfflag', 'Requires: active-client'), which implies when the call is usable, but there is no explicit guidance on when to prefer this over alternatives such as set-fast-flag or the broader runtime-inspection tools. Usage is inferable rather than spelled out.

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