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

With no annotations, the description carries the full burden. It usefully discloses that the return is cumulative elapsed time plus a Chinese-readable duration, and the '会话级' framing hints at session-scoped persistence. However, it says nothing about destructive behavior of reset, restart semantics of start on an existing clock, or multi-clock isolation, leaving notable behavioral gaps.

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 front-loaded sentence packs the resource and all five action meanings with essentially zero filler. Slightly dense but appropriately sized for the tool's scope.

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?

There is no output schema, so the description must cover returns — and it does, naming cumulative timing and a readable duration. Given a 4-parameter, single-required-param stateful tool with full schema coverage, the only real omission is guidance on sibling selection and mutation/restart semantics.

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 the schema already documents action, clock_id, timezone, and session_id in detail. The description merely repeats the action glosses without adding format, default, or interaction semantics (e.g., how clock_id and session_id combine), so it lands at the baseline.

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 resource ('会话级计时器') and enumerates all five operations with their Chinese glosses, so an agent immediately knows this is a stateful session timer rather than a one-shot time query. It does not name any sibling (duration_elapsed, current_time) to distinguish scope, so it falls short of a 5.

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 action enumeration implies the operating modes, but there is no explicit when-to-use guidance or routing against siblings like duration_elapsed or current_time. Usage must be inferred from the verb list 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?

With no annotations, the description carries the burden and largely meets it: it explicitly says no real timer is started (no side effects) and enumerates the return payload (hit yes/no, next and previous trigger instants, countdown). It omits permission/rate-limit or evaluation-failure behavior, keeping it from a 5.

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 dense sentence, front-loaded with the core purpose, followed by a short clarifying clause about no real timer. Every element earns its place; slight density costs it the top score.

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?

No output schema exists, so the description correctly supplies the return values, and with no annotations it discloses the key mock/no-side-effect trait. Only the cross-tool routing and failure semantics are left thin.

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 now/schedule/timezone are already documented; baseline 3 applies. The description's mention of accepted schedule syntax echoes the schema field rather than adding new meaning, and it never mentions timezone evaluation.

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+resource: it evaluates whether a schedule ('cron / @macro / every 30 minutes') is due 'now' and reports hit/last/next/countdown. That is clearly distinguishable from time-arithmetic siblings. It stops short of naming which sibling to use instead, so not a 5.

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: evaluate cron-style schedules and, per '不启动真实定时器', use it in a dry-run/mock context rather than scheduling anything real. However, it names no alternative (time_until, current_time) and gives no explicit when/when-not conditions.

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?

No annotations are provided, so the description carries the full burden. It does disclose the returned fields (time, date, weekday, timezone, UTC offset), which is genuine behavioral value, but it says nothing about the system-timezone default behavior, output format, or precision. For a side-effect-free read tool this is adequate but thin.

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 compact sentence with the core resource front-loaded. The trailing parenthetical paraphrases the same fields in colloquial query terms, which adds mild value for matching but is partly redundant.

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?

No output schema exists, so the description does well to enumerate the returned fields, and the single optional parameter is fully covered by the schema. The remaining gap is the absence of any guidance versus the heavily overlapping siblings, which matters given the crowded namespace.

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%, and the single timezone parameter is well documented in the schema (IANA name, system default fallback). The description only alludes to timezone as a returned value, adding no syntax or semantics beyond the schema, so the baseline of 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 specific verb+resource: returns the current time, date, weekday, timezone, and UTC offset. An agent can tell this is a 'get current clock state' tool, but the description does no work to separate it from the near-identical sibling agent_clock or from timezone_convert, so sibling differentiation is missing.

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?

There is no when-to-use guidance, no exclusions, and no reference to any alternative. With siblings like agent_clock and timezone_convert in the same namespace, the agent gets no help deciding which to call; usage must be inferred entirely from the name.

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?

With no annotations, the description carries the full burden and does disclose the stateful lifecycle: auto-start on first call, cumulative return thereafter, and reset behavior. It omits other traits an agent would want, such as whether state persists across sessions/connections, what happens with a supplied started_at, or any error behavior.

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: the core purpose comes first, followed by the lifecycle rules in semicolon-separated clauses. Every clause earns its place with no filler, though the density leaves some behavior (return format) unaddressed rather than 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?

No output schema exists, so the description should at least sketch what is returned; it states only conceptually that it returns 'how long has elapsed' without unit/format. Given all six parameters are well documented in the schema and the lifecycle is covered, the definition is adequate but not fully 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 description coverage is 100%, so all six parameters are already documented in the schema and the baseline is 3. The description reinforces the reset (restart timing) and auto-start (started_at) semantics but adds no syntax, format, or default details beyond what the schema already states.

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+resource: it records a task start moment and returns elapsed time, which is a clear, distinct purpose. It does not explicitly name or contrast against siblings such as time_until, current_time, or agent_clock, so an agent must infer the difference from the cumulative-per-session semantics.

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 clearly explains the call lifecycle (first call auto-starts, later calls return cumulative duration, reset=true restarts), which is useful implied usage guidance. However, it never states when to prefer this tool over siblings like time_until or current_time, so alternative routing is left 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?

With no annotations, the description carries the full burden and does disclose the key hidden trait: it is a state-mutating call that updates a timestamp, despite looking like a harmless clock query. It also states the two values returned. It omits any note on persistence, permissions, or what happens on concurrent/first-ever calls.

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?

One dense sentence with the action, cadence and return payload front-loaded; almost nothing is wasted. It is slightly packed with three ideas at once, but none 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-optional-param tool with no output schema and no annotations, the description covers purpose, cadence and return values, which is close to sufficient. Missing only the edge-case behaviour (first call with no prior timestamp, per-session accumulation semantics) and sibling disambiguation.

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 timezone and session_id are already fully documented in the schema (including the default and the accumulation behaviour). The description adds nothing about either parameter, 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?

The description names a specific action (会话心跳/更新 time stamp) and its two outputs (距上次对话间隔、本会话总时长), so the verb+resource+return is clear. It does not, however, distinguish itself from near-neighbours such as duration_elapsed or current_time, which also deal with elapsed time.

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 gives an explicit invocation cadence: '每次对话调用一次' — an agent knows exactly when to fire it. It offers no when-not condition and never routes to the overlapping siblings (duration_elapsed, current_time), so it stops short of full alternative guidance.

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?

With no annotations, the description carries the full burden. It usefully discloses that a past target yields the elapsed duration instead of an error, which is a real behavioral trait. But it says nothing about how the result is formatted, how from/timezone interact, or error handling for invalid input.

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 compact sentence, front-loaded with the core action and parenthetically covering the inverted-case behavior. Every clause earns its place with no redundancy.

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 3-parameter tool with no output schema and no annotations, the description omits the return type/format and the from/timezone interaction. It is minimally adequate but leaves the agent guessing about output shape and edge-case semantics.

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 all three parameters (from, target, timezone) are already documented with formats and defaults in the schema. The description adds no parameter-level detail beyond that, so the baseline of 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 specific verb and resource ('計算距離目標/截止時刻還剩多久') plus the edge case when the target has passed. An agent can immediately tell this computes a countdown, though it doesn't explicitly contrast with the closest sibling duration_elapsed.

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 by the countdown-to-a-deadline framing ('目標/截止時刻'), which gives an agent enough to know the context. However, no explicit when-to-use or when-not guidance is given, and no alternatives are named despite siblings like duration_elapsed and timezone_convert that overlap conceptually.

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?

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses the response content (target-zone local time plus the offset delta), which compensates somewhat for the missing output schema, but it is silent on defaults and on how DST-ambiguous or invalid timezones are handled.

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 front-loaded sentence states the operation and the return values with zero filler. Nothing is padded or redundant.

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 three-parameter compute tool with no output schema, the description covers the operation, the directional conversion, and the return shape, with defaults handled in the schema. Only the when-to-use guidance against sibling time tools 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% — all three parameters carry their own descriptions including the ISO 8601 format and default behaviors for time and from_timezone. The description adds no parameter-level meaning beyond what the schema already documents, so the 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?

The description states a specific verb+resource combination (convert a moment from a source timezone to a target timezone) and even names the return values (target local time and offset difference). It is clear what the tool does, but it does not differentiate itself from siblings such as current_time or time_until, so an agent must infer the boundary itself.

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 only implied: 'convert a moment from timezone A to timezone B' tells the agent the scenario but never states when to prefer this over current_time or how it relates to the other time siblings. No exclusions or prerequisites are given.

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