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

Annotations already provide readOnlyHint=false, destructiveHint=true, and openWorldHint=true. The description adds behavioral context about requiring a recent screenshot and prohibiting held keys, but does not describe side effects, permissions, or response behavior. It does not contradict the annotations.

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?

Two short sentences, each earning its place. The first is the action and purpose, the second is a constraint. No wordy filler or repetition of schema information, and the key action is front-loaded.

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 tool taking only two integers and no output schema, the description explains the source of coordinates, the intended action, and an important constraint. It doesn't mention return values or failure modes, but a click action with minimal parameters is adequately specified without them.

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 0%, so the description must carry the meaning of x and y. The phrase 'viewport coordinates' does add semantics, indicating the numbers are pixel coordinates in the viewport shown in the screenshot. However, it doesn't specify the coordinate origin (e.g., top-left) or units, leaving some ambiguity.

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 'Click' and a specific resource 'viewport coordinates from a recent screenshot', with the clear purpose 'to focus or activate the piano'. This distinguishes it from siblings like key_down/key_up, which are about keyboard events, and browser_screenshot which captures the image.

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?

Provides clear context by specifying the coordinates come from a recent screenshot, implying the agent should take a screenshot first. The 'No keys may be held' constraint is a limiting rule. It doesn't name alternative tools explicitly, but the distinction from key-based interactions is clear enough for an agent to infer when to use it.

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

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

Annotations already mark it destructive, but the description adds valuable order of operations: first stop input, then release keys, then close the browser. It also names the uniquely dedicated browser, providing context beyond the bare annotation.

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?

A single concise sentence covers the purpose and action sequence with no wasted words. Every element—stop, release, close—adds 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?

The description is sufficient for a parameterless destructive close operation. It tells the agent exactly what will happen and the order of operations. It could mention the connection to browser_open but the 'dedicated browser' wording implies a managed session, so it is acceptable.

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?

The tool has zero parameters, so the schema needs no explanation. The description is accurate; baseline 4 applies because there are no parameters to describe.

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?

The description states a clear, specific sequence of actions: stop input, release keys, and close the dedicated browser. This distinguishes it from siblings like release_all and browser_open without requiring schema inspection.

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?

Usage is implied but not explicit. The description conveys that this is the cleanup action that both releases keys and closes the browser, which hints at when to use it, but it does not explicitly name alternatives or state conditions such as 'use when done with the browser session'.

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

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

Annotations already indicate readOnly=false and destructiveHint=true, so the description builds on them by adding that the window is temporary and that the URL must be user-authorized. This goes beyond the structured annotations and does not contradict any of them.

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?

Two sentences, front-loaded with the core action, followed by isolation and authorization guidance. Every sentence adds meaningful information and there is no redundancy or 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 one-parameter tool with no output schema, the description covers purpose, standout behavioral traits, and URL authorization. It does not state what value is returned or how the temporary window is tracked later, but this is minor given the sibling context and simplicity.

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?

With 0% schema description coverage, the description compensates by framing the 'url' parameter as requiring user authorization, adding meaning beyond the bare 'string + uri' schema. It could go further by explaining constraints on the URL value, but what is present is genuinely useful.

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?

The description uses a clear verb ('Open') and resource ('dedicated, temporary Chromium window'), and distinguishes itself from siblings by stating it does not attach to personal browser tabs. This gives an agent enough to understand exactly what the tool does and how it differs from browser_status, browser_click, etc.

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 description provides clear context for using the tool: a temporary window, isolated from personal browser tabs, with a user-authorized URL. It does not explicitly name alternatives or exclusion conditions, but the context is strong enough for typical agent selection.

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

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

Annotations already declare readOnlyHint=true, lowering the bar. The description adds a valuable warning that page content is untrusted, which is critical behavioral context for an agent using the screenshot to make decisions. It also clarifies that it captures the current viewport, defining the scope of the operation.

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 description is exactly two sentences with zero fluff. The first sentence delivers purpose and usage in one compact clause; the second delivers a critical trust warning. Information is front-loaded and every word 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?

For a zero-param, no-output-schema tool, the description covers purpose, usage, and a security warning. It doesn't specify output format (e.g., image path vs. base64), but for a screenshot this is often implicit or handled by the agent's runtime. It provides enough for a correct invocation.

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?

The tool has zero parameters, so the schema is trivial and the description need not explain parameters. Baseline for no-param tools is 4; the description correctly avoids adding meaningless detail about nonexistent inputs.

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?

The description states the tool inspects the current viewport, which clearly implies a screenshot. It also ties the purpose to a workflow step ('before choosing click coordinates'), distinguishing it from sibling interaction tools like browser_click. The verb 'inspect' is slightly indirect but the meaning is unambiguous given the tool name.

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 instructs when to use it: before choosing click coordinates, framing it as a reconnaissance step. While it doesn't name alternatives like browser_click, it gives a clear contextual trigger that implies this is the visual verification tool. This is sufficient guidance for an agent to decide when to invoke it.

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

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

Annotations already indicate a read-only, non-destructive, open-world operation. The description adds useful context by enumerating exactly what state is read: session data, held keys, latest sequence result, and dispatch lateness. It does not contradict the annotations and adds meaningful behavioral detail.

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 description is a single compact sentence with no filler. It front-loads the core action and each added clause contributes useful information.

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 zero-parameter status-read tool, the description names the relevant state categories and is sufficiently complete. There is no output schema, so the description partially stands in for return-value expectations; while it might have described the shape in more detail, it is adequate for this simple tool.

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?

The tool has zero parameters, so the schema already fully covers the invocation surface. The description provides all necessary contextual meaning, and the baseline for zero-parameter tools is a 4.

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?

The description clearly names a specific read operation and the resources being inspected: the session, held keys, and latest sequence result including dispatch lateness. This makes it easy to distinguish browser_status from the mutation/control sibling 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?

The description implies when the tool is useful — when the agent needs to inspect current session/input state — but it does not explicitly state when to use it over alternatives or provide exclusions. It is minimally adequate but leaves the decision to inference.

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

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

Beyond annotations (which indicate destructive/open-world), the description discloses that the tool returns immediately and that completion must be checked via browser_status. This adds crucial async-behavior context. There is no contradiction with the destructiveHint annotation.

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?

Three short, meaningful sentences. The main purpose is front-loaded, then the return behavior, then the completion-check instruction. No word is wasted.

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?

Given a simple 2-parameter tool with no output schema, the description covers the action, the timing, and the follow-up channel (browser_status). It omits only a deeper discussion of side-effects, but the annotations already indicate destructiveness.

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?

With 0% schema description coverage, the description carries the parameter explanation. It clearly links 'keys' to the overlapping chord elements and 'durationMs' to how long they are held before release, which is sufficient for correct use.

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?

The description clearly states the action: starting a chord with overlapping keys and releasing them after a duration. It names the resource (keys) and behavior (overlapping, auto-release), which differentiates it from siblings like key_down/key_up or sequence_start.

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 description implies when to use: when you need overlapping key presses for a duration. However, it does not explicitly contrast with key_down, key_up, sequence_start, or mention situations where this tool would be inappropriate. Usage is evident but not explicitly enumerated.

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

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

Beyond the annotations, it discloses auto-release timing (default 5000, max 30000), overlapping key behavior, and the no-modifier-shortcuts limitation. This adds meaningful behavioral context on top of destructiveHint and openWorldHint. It doesn't describe OS-level side effects, but the annotations already flag destructiveness.

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?

Two short sentences front-load the action and then add constraints. No filler, and every sentence contributes useful information for invoking the tool correctly.

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 tool with no output schema, the description covers the core invocation details: which key to hold, how long, and overlap behavior. It doesn't mention early release via key_up or release_all, but those are sibling tools and not required for correct invocation of key_down.

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?

With 0% schema description coverage, the description must carry parameter meaning. It gives an example key format ('KeyA') and explains holdMs semantics with default/max values. However, it mostly restates schema constraints and doesn't clarify the full key pattern or that holdMs is optional.

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?

The description uses a specific verb ('Hold') and resource ('physical key') with an example key name, making the action unambiguous. It also distinguishes itself from key_up by emphasizing automatic release, though it doesn't explicitly name sibling alternatives.

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?

It provides useful context: other keys can overlap, auto-release happens after holdMs, and modifier shortcuts are not supported. However, it doesn't explicitly say when to prefer this over chord, key_up, or sequence_start, so usage guidance is implied rather than stated.

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

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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the mutating nature is covered. The description adds the context that the key must be held and the sequencing note, but does not disclose potential side effects (e.g., if the key is not held) or error behavior. Given annotations carry the safety profile, this is adequate but not rich.

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?

Two sentences with zero filler. The primary purpose is front-loaded, and the only additional sentence is a critical usage caveat. No redundant information; every word 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?

For a simple one-parameter action, the description covers the core intent and the most important alternative (sequence_stop). It doesn't specify return values or error conditions, but given the simplicity and lack of output schema, these are minor omissions. An agent can infer the inverse relationship with key_down and the distinction from release_all from the name and context.

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 0%, so the description must add meaning beyond the pattern-based schema. It clarifies that the 'key' parameter refers to a physical key currently held, which is not in the schema. However, it does not provide examples or further format guidance beyond what the pattern already enforces. The added value is modest but sufficient for a single parameter.

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?

The description states a clear, specific verb ('Release') and object ('one held physical key'), which immediately distinguishes it from siblings like key_down (press) and release_all (release all keys). The mention of 'physical key' adds precision, and the alternative mention of sequence_stop further clarifies scope.

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 to use this tool ('Release one held physical key') and when not to: 'Use sequence_stop while a sequence is running.' This names the alternative tool and the condition that overrides this one, giving the agent an unambiguous decision rule.

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

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

Annotations already declare destructiveHint=true and openWorldHint=true, so the description adds the specific behavioral scope of 'any' and 'every' to clarify the breadth of the side effect. It does not reveal the full consequence of releasing every tracked key, such as whether state can be recovered, but given the annotations this is adequate.

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 entire description is one tight sentence of eight words, combined two actions with clear scope. No fluff, no repetition, and the key side effect is front-loaded. This is an exemplary concise definition.

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 parameters and no required arguments, the description fully specifies what the tool does: it stops any running sequence and releases every tracked key. Given the simple action and zero-param signature, there is nothing critical missing for an agent to invoke it effectively.

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?

The tool has zero parameters, and the schema coverage is 100% (empty schema). The description correctly captures everything a parameter could convey. The baseline for 0 params is 4, which fits here.

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?

The description states a specific verb and resource: stops any running sequence and releases every tracked key. The scope ('any', 'every') distinguishes it from siblings like sequence_stop and key_up without naming them explicitly. It is clear and actionable, though it could have explicitly differentiated from those siblings.

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 usage context is implied: this is the comprehensive stop/release tool for clearing all sequence and key state. However, it does not explicitly state when to choose it over sequence_stop or key_up, nor does it mention any preconditions or exclusions. An agent can infer but is not directly guided.

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

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

Beyond annotations (destructive, open-world), the description adds behavioral details such as immediate return, best-effort timing, and the requirement for balanced pairs, giving a fuller picture of what happens when called.

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?

Each sentence delivers a distinct piece of information without redundancy, making it concise and well-structured for quick comprehension.

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?

It covers key operational aspects (start, constraints, return behavior, timing reliability) and mentions related tools for follow-up (browser_status, sequence_stop), making it fairly complete for an agent to decide and invoke correctly.

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?

The description clarifies the meaning of atMs (absolute offset from start, max 30s) and explains ordering for equal timestamps, adding value beyond the raw schema which only lists types and ranges.

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?

The description clearly states the tool starts a sequence of timed key events, with specifics like absolute offsets, max duration, and overlap capability, distinguishing it from siblings like key_down or key_up.

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?

It provides some usage constraints (balanced down/up pairs, no holds, immediate return) and mentions inspecting browser_status or stopping with sequence_stop, but does not explicitly contrast with alternatives like key_down or chord for when this tool is preferred over them.

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

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

Annotations already indicate mutating (readOnlyHint=false) and destructive (destructiveHint=true) behavior, so the description builds on that by specifying exactly what happens: interrupting the sequence and releasing all held keys. This adds concrete behavioral detail beyond the annotations, though it doesn't describe edge cases like whether it fails if no sequence is running.

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 description is a single, dense sentence that front-loads the primary action and its outcome. Every word earns its place; there is no redundancy or 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 simple zero-argument, no-output tool, the description is nearly complete. It states the action and result. The only minor gap is the lack of explicit differentiation from release_all, but given the tool's simplicity and the annotations already covering safety, the description is effectively sufficient.

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?

The tool has zero parameters, so the description carries no burden to explain parameter semantics. The baseline of 4 applies because there is nothing to add; the schema is trivially complete.

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?

The description states a specific verb ('Interrupt') and resource ('running sequence') plus the immediate effect ('release all held keys'). It clearly distinguishes this from sequence_start (starts a sequence) and release_all (releases keys but not specifically tied to a running sequence). No ambiguity remains about what the tool does.

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 description implies when to use it (to stop a running sequence) but does not explicitly contrast with siblings like release_all or key_up. An agent must infer the differentiation from the name and context rather than receiving direct guidance. This is adequate but not explicit.

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