press_keys

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

Annotations only declare it is not read-only and not destructive. The description adds real behavioral context beyond that: the focus-targeting requirement (input goes to whatever has the keyboard), and the cross-call persistence of state=down until a state=up call — a stateful side effect an agent must know. Does not cover error behavior or what happens with invalid key names.

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 before conditions and parameter nuance, and it is tightly packed without filler. The parenthetical chord list (Tab, Return, Escape, ctrl+s, alt+shift+Tab, F6) is illustrative padding that could be trimmed, but each remaining sentence carries meaning.

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 4 parameters, no output schema and minimal annotations, the description covers the essential unknowns: focus targeting, chord sequencing, hold duration, and cross-call key state. It does not address return values or failure modes, but for a 60-second-bounded input tool this is close to complete.

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 baseline is 3, but the description earns more by explaining semantics the schema cannot: the 'walking while running' analogy for hold, and that state down persists across calls while state up releases. Chord examples (ctrl+s, alt+shift+Tab) also clarify the keys array format beyond 'Chords, pressed one after another'.

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 and resource ('Press keys in turn, each a chord') with concrete examples of what a chord is. The scope is unambiguous. However, it never names or contrasts with the adjacent sibling type_text, which is the most likely confusion point for an agent choosing between keyboard tools.

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?

Gives clear operational context: keys go to whatever holds focus, and 'click a window first if nothing does' handles the precondition. It also distinguishes when to use hold (simultaneous press with a duration) vs state down/up (persistent press across calls). No explicit exclusion naming type_text as the alternative for free text.

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