paste

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

With no annotations, the description carries the full behavioral burden and does so well: it states a precondition (tap the field first so it has focus), the return shape ({ pasted: true }, plus via: "keyboard" when a secret was typed), and multiple failure modes (TV target, unsettable device clipboard, untypable secret characters, simulator-server lacking clipboard support). It also discloses secret-handling behavior (value never echoed back).

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 purpose and mechanism, then the exclusion, then the use cases, then behavior. Every sentence earns its place; the length is justified by the behavioral disclosures and no sentence is filler.

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 2-parameter tool with no output schema, the description covers purpose, alternative routing, preconditions, return value, and failure modes. Nothing an agent needs to invoke it correctly 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 coverage is 100%, so the schema already documents both parameters, making 3 the baseline. The description adds value beyond that by reiterating the secret placeholder mechanism and adding the non-echo guarantee, plus the shared-source behavior with `keyboard`.

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?

Names a specific verb+resource (paste text into the focused field) and immediately explains the mechanism (device clipboard + platform paste shortcut on iOS simulator / Android emulator). It distinguishes itself from the sibling `keyboard` right away, so an agent can tell the two apart without opening a 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 states when NOT to use it ("Do NOT use this in place of `keyboard`") and gives concrete when-to-use cases: 2FA/OTP codes, long links or tokens, testing the app's own paste handling. It also names the default alternative and its rationale (keyboard types as a user would and is default for all text entry).

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