clipboard

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

With annotations only covering readOnly=false/idempotent=true/destructive=false, the description carries the interesting behavior itself: security codes are masked, a lone code/password/token is never shown, read may report empty or non-text, and write has a 256 KB cap and overwrites the user's existing clipboard. That overwrite disclosure is a side effect the annotations do not convey and materially affects how an agent should call it.

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?

Compact and front-loaded, with 'read:'/'write:' labels that let an agent scan straight to the relevant mode. The clause 'or says it is empty or not text' is slightly awkward, but 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 two-parameter, no-output-schema tool, the description covers both directions of behavior, content limits, redaction rules, and the overwrite side effect. Only the return value of write (confirmation vs. nothing) is left unstated.

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 0%, so the description must compensate, and it largely does: it explains what `text` accepts (accents, emoji, 256 KB max) and defines both meanings of `action`. It does not mention that `action` defaults to 'read' or that `text` may be null, leaving a small gap the schema alone does not explain.

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 the resource ('the phone's clipboard') and splits it into two explicit modes with specific verbs: read returns its text (or reports empty/non-text), write places `text` into it. The phrase 'without pasting it anywhere' implicitly separates it from the sibling `act`/paste path, so an agent can tell what it does and does not do.

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?

The read/write framing gives clear operational context for each action, and 'without pasting it anywhere; it replaces what the user had copied' is a real caveat that steers the agent away from treating write as a paste. It stops short of naming an alternative tool or stating explicit when-not conditions, so it sits just below the top band.

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