Set the .Text of a GUI element

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

Goes well beyond the annotations: discloses that FocusLost/text-changed events do NOT fire, that reads/writes are pcall-guarded, and returns { Path, OldText, NewText, ok } for auditability. Safety traits (mutating, destructive, non-readOnly) agree with the annotations. Minor tension: the metadata line says 'idempotency=idempotent-write' while the annotation sets idempotentHint=false, though the practical effect (setting a fixed string) is harmless to retry.

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 critical warning 'WRITES LIVE GAME STATE' and organized into purpose, caveats, return shape, and metadata. Slightly long due to the boilerplate trailing 'On failure: inspect tool-schema...' line, but nearly 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?

Despite no output schema, the description fully specifies the return shape ({ Path, OldText, NewText, ok } or { error }), the mutation warning, prerequisites (active-client, explicit-mutation-approval), and verification (get-gui-text). Nothing an agent needs to invoke it safely 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%, so path/text/threadContext are already fully documented in the schema, including the Luau expression form and 'written verbatim'. The description's 'Signature:' line only restates the schema, adding no new parameter meaning, so baseline 3 applies.

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 precise verb+resource: 'Resolve a Luau expression to a GUI Instance and overwrite its .Text property.' It is clearly distinguishable from siblings get-gui-text (read), type-text-box/click-button (input simulation), and set-instance-property (generic property write).

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?

Explicit when-to-use ('pre-fill a login/search box or change a label while debugging UI logic') and when-not, naming the alternative: 'use type-text-box with useKeyPress when you need real keystroke side-effects.' This gives an agent a clean routing rule.

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