Server Quality Checklist

Tool Scores

• cancel_sleep_timerC
  2.9/5.0
  Behavior2/5

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

  With no annotations, the description carries full burden but only states the basic action. It lacks details on behavioral traits such as permissions needed, whether cancellation is reversible, error handling, or confirmation of success, which are critical for a mutation tool.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is a single, efficient sentence with zero waste, front-loaded with the core action. It's appropriately sized for a simple tool, earning full marks for conciseness.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness2/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  For a mutation tool with no annotations and no output schema, the description is incomplete. It doesn't address behavioral aspects like side effects, return values, or error conditions, leaving significant gaps in understanding how to use it effectively.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  Schema description coverage is 100%, so the schema fully documents the optional 'timerId' parameter. The description adds no parameter semantics beyond what the schema provides, maintaining the baseline score of 3 for high schema coverage.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose4/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the action ('Cancel') and target ('an active sleep timer'), providing specific verb+resource. However, it doesn't differentiate from sibling tools like 'get_active_timers' or 'set_sleep_timer' beyond the basic operation, missing explicit sibling distinction.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  No guidance is provided on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., requires an active timer), exclusions, or contextual cues, leaving usage unclear relative to siblings like 'get_active_timers' or 'set_sleep_timer'.

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

• play_albumC
  2.9/5.0
  Behavior2/5

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

  With no annotations provided, the description carries full burden but only states the basic action. It doesn't disclose behavioral traits like whether this requires authentication, affects current playback, has rate limits, or what happens on errors (e.g., if album not found). For a mutation tool with zero annotation coverage, this is a significant gap.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  Extremely concise and front-loaded in a single sentence that directly states the tool's purpose. Every word earns its place with no redundant information, making it easy to parse quickly.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness2/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given no annotations, no output schema, and a mutation tool (implied by 'Play'), the description is incomplete. It lacks crucial details like authentication requirements, playback behavior, error handling, or return values, leaving significant gaps for an agent to use it effectively.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  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 all three parameters (albumName, artistName, deviceId). The description adds minimal value by mentioning 'optional artist' but doesn't provide additional context beyond what's in the schema, such as how artistName helps disambiguate or typical deviceId formats.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose4/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the verb ('Play') and resource ('a Spotify album'), specifying it's by name with optional artist filtering. It distinguishes from siblings like play_playlist, play_track, and play_random_song by focusing on albums, but doesn't explicitly differentiate from other album-related tools (none listed).

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  No guidance on when to use this tool versus alternatives like play_playlist or play_track, nor any context about prerequisites (e.g., requires active Spotify session). The description implies usage for playing albums but lacks explicit when/when-not instructions or named alternatives.

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

• play_playlistC
  2.9/5.0
  Behavior2/5

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

  With no annotations provided, the description carries full burden for behavioral disclosure. While 'Play' implies a write/mutation operation, it doesn't specify whether this requires specific permissions, what happens if the playlist isn't found, whether playback interrupts current audio, or any rate limits. This leaves significant behavioral gaps for a mutation tool.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is a single, efficient sentence that communicates the core purpose without any wasted words. It's appropriately sized for a simple tool and gets straight to the point.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness2/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  For a mutation tool with no annotations and no output schema, the description is insufficient. It doesn't explain what happens on success/failure, return values, error conditions, or behavioral constraints. Given the complexity of media playback and the lack of structured data, more context is needed.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  Schema description coverage is 100%, so both parameters are documented in the schema. The description adds no additional parameter semantics beyond what's already in the schema (playlistName and optional deviceId). This meets the baseline for high schema coverage but doesn't provide extra value.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose4/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the action ('Play') and resource ('a Spotify playlist by name'), making the purpose immediately understandable. However, it doesn't differentiate from sibling tools like play_album or play_track, which perform similar playback actions on different resource types.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description provides no guidance on when to use this tool versus alternatives like play_album, play_track, or play_random_song. It also doesn't mention prerequisites such as needing an active Spotify session or available devices, which are critical context for playback tools.

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

• play_random_songC
  2.9/5.0
  Behavior2/5

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

  With no annotations, the description carries the full burden of behavioral disclosure. It states the action ('Play') but lacks details on authentication needs, rate limits, or what happens if no device is specified. This leaves significant gaps for a tool that interacts with an external service like Spotify.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is a single, efficient sentence that directly states the tool's function without any wasted words. It's appropriately sized and front-loaded, making it easy to parse quickly.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness2/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  For a tool with no annotations, no output schema, and interaction with an external service (Spotify), the description is incomplete. It lacks crucial context such as authentication requirements, error handling, or what 'random' entails (e.g., from user's library or global catalog), leaving the agent under-informed.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  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 the single optional parameter 'deviceId'. The description doesn't add any parameter-specific information beyond implying playback, which is inherent in the tool's purpose. This meets the baseline for high schema coverage.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose4/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the action ('Play') and resource ('a random song from Spotify'), making the purpose immediately understandable. However, it doesn't differentiate from siblings like 'play_track' or 'play_album' beyond the 'random' aspect, which is why it doesn't reach a perfect score.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  No guidance is provided on when to use this tool versus alternatives like 'play_track' or 'play_playlist'. The description implies randomness but doesn't specify contexts where this is preferred over selecting specific songs, leaving the agent with little direction.

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

• play_trackC
  2.9/5.0
  Behavior2/5

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

  With no annotations, the description carries the full burden but provides minimal behavioral insight. It mentions playing a track but doesn't disclose effects (e.g., interrupts current playback, requires active device, authentication needs, or rate limits). This is inadequate for a mutation tool with zero annotation coverage.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is a single, efficient sentence with zero waste. It is appropriately sized and front-loaded, directly stating the tool's purpose without unnecessary elaboration.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness2/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given the tool's complexity (a mutation operation with no annotations and no output schema), the description is insufficient. It lacks details on behavioral traits, return values, error handling, or how it interacts with sibling tools, leaving significant gaps for an AI agent.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  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 all parameters. The description adds marginal value by implying that artistName helps disambiguate tracks, but doesn't provide syntax or format details beyond what the schema offers. Baseline 3 is appropriate as the schema does the heavy lifting.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose4/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the action ('Play') and resource ('a specific track'), with additional context about identification by name and optional artist. It distinguishes from siblings like play_album or play_playlist by focusing on individual tracks, though it doesn't explicitly contrast with play_random_song or control_playback.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  No guidance is provided on when to use this tool versus alternatives like play_album, play_playlist, play_random_song, or control_playback. The description implies usage for playing a known track, but lacks explicit context, prerequisites, or exclusions.

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

• search_musicC
  2.9/5.0
  Behavior2/5

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

  With no annotations provided, the description carries the full burden of behavioral disclosure. It states what the tool does but lacks critical behavioral details such as whether this is a read-only operation, how results are returned (e.g., pagination, format), rate limits, or authentication requirements. For a search tool with zero annotation coverage, this is a significant gap.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is a single, efficient sentence that front-loads the core purpose without any wasted words. It directly communicates the tool's function in a clear and structured manner, making it easy to parse quickly.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness2/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given the complexity of a search tool with no annotations and no output schema, the description is incomplete. It doesn't explain what the return values look like (e.g., structured data with tracks/albums/artists), how results are filtered, or any error handling. This leaves the agent with insufficient context for effective use.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  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 both parameters ('query' and 'limit') adequately. The description adds no additional parameter semantics beyond what's in the schema, such as query format examples or limit constraints. Baseline 3 is appropriate when the schema does the heavy lifting.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose4/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the action ('Search for music') and the resource ('tracks, albums, artists on Spotify'), making the purpose immediately understandable. However, it doesn't explicitly differentiate from sibling tools like 'play_track' or 'play_album', which are playback rather than search operations, so it misses full sibling distinction.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description provides no guidance on when to use this tool versus alternatives. It doesn't mention when to prefer search over direct playback tools like 'play_track' or how it relates to other search-like functions that might exist in the context. This leaves the agent without contextual usage cues.

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

• get_active_timersB
  3.2/5.0
  Behavior2/5

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

  No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool retrieves a list but doesn't describe format, ordering, pagination, error conditions, or whether it requires specific permissions. For a read operation with zero annotation coverage, this leaves significant gaps in understanding how the tool behaves.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is a single, efficient sentence that directly states the tool's purpose without unnecessary words. It is front-loaded with the core action ('Get list'), making it easy to parse. Every word earns its place, with no redundancy or fluff.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness3/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given the tool's simplicity (0 parameters, no output schema, no annotations), the description is minimally adequate. It covers the basic purpose but lacks details on return format, error handling, or device context that would help an agent use it effectively. For a read operation in a music/sleep timer system, more context about what 'active' means would improve completeness.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters4/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  The tool has 0 parameters with 100% schema description coverage, so the schema fully documents the absence of inputs. The description adds no parameter information, which is appropriate here. A baseline of 4 is applied for zero-parameter tools, as no additional semantic explanation is needed.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose4/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the verb ('Get') and resource ('list of active sleep timers'), making the purpose unambiguous. It distinguishes from siblings like 'cancel_sleep_timer' by focusing on retrieval rather than modification. However, it doesn't specify scope (e.g., all devices or current session) which prevents a perfect score.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  No explicit guidance is provided on when to use this tool versus alternatives. The description doesn't mention prerequisites, timing considerations, or relationships to sibling tools like 'cancel_sleep_timer' or 'set_sleep_timer'. The agent must infer usage from the tool name alone.

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

• get_current_playingB
  3.2/5.0
  Behavior2/5

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

  No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool retrieves information, implying a read-only operation, but doesn't clarify aspects like authentication needs, rate limits, error conditions (e.g., if nothing is playing), or response format. For a tool with zero annotation coverage, this is a significant gap in transparency.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is a single, efficient sentence that directly states the tool's function without unnecessary words. It's front-loaded with the core purpose ('Get information'), making it easy for an agent to parse quickly. Every part of the sentence earns its place by specifying what is retrieved.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness3/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given the tool's low complexity (0 parameters, no output schema, no annotations), the description is minimally adequate. It covers the basic purpose but lacks details on behavior, usage context, or output expectations. For a simple read operation, this might suffice, but it doesn't provide a complete picture for optimal agent use.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters4/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  The tool has 0 parameters, and schema description coverage is 100%, so the schema fully documents the lack of inputs. The description doesn't need to add parameter details, and it correctly implies no inputs are required. Baseline 4 is appropriate for zero-parameter tools with complete schema coverage.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose4/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the tool's purpose with a specific verb ('Get') and resource ('information about the currently playing track'). It distinguishes from siblings like 'get_devices' or 'get_active_timers' by focusing on playback status. However, it doesn't explicitly differentiate from potential similar tools (e.g., if there were a 'get_playback_state' tool), keeping it at 4 rather than 5.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., requires active playback), exclusions (e.g., not for historical data), or comparisons to siblings like 'control_playback' or 'search_music'. This leaves the agent with minimal context for tool selection.

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

• set_default_deviceB
  3.2/5.0
  Behavior2/5

  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 states this is a mutation ('Set'), implying it changes system state, but doesn't disclose behavioral traits like required permissions, whether the change is persistent, error conditions, or side effects. This is a significant gap for a mutation tool with zero annotation coverage.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is a single, efficient sentence with zero waste. It's front-loaded with the core purpose and appropriately sized for a simple tool with one parameter.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness2/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given this is a mutation tool with no annotations and no output schema, the description is incomplete. It lacks behavioral context (e.g., what happens on success/failure, whether it affects active playback), and while the parameter is covered, the overall tool behavior is underspecified for safe agent use.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  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 the single parameter 'deviceId'. The description adds no additional meaning beyond what the schema provides (e.g., format examples, sourcing instructions, or validation rules). Baseline 3 is appropriate when the schema does the heavy lifting.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the specific action ('Set') and resource ('default Spotify device ID'), and specifies the scope ('for all playback operations'). It uses precise language that distinguishes it from sibling tools like 'get_devices' or 'control_playback'.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an active device list from 'get_devices'), exclusions, or contextual triggers. The agent must infer usage from the purpose alone.

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

• set_sleep_timerB
  3.2/5.0
  Behavior2/5

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

  No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool sets a timer to pause playback, but lacks details on permissions needed, whether it overrides existing timers, error conditions (e.g., invalid duration), or response format. For a mutation tool with zero annotation coverage, this is a significant gap in transparency.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is a single, efficient sentence that directly states the tool's purpose without unnecessary words. It is front-loaded with the core action and outcome, making it easy to parse quickly, with no wasted information.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness2/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given the tool's complexity (a mutation with no annotations and no output schema), the description is incomplete. It fails to address key contextual aspects such as what happens if a timer is already set, whether the tool returns confirmation, or error handling for invalid inputs, leaving gaps for an AI agent to understand full behavior.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  The schema description coverage is 100%, with the single parameter 'durationMinutes' fully documented in the schema. The description adds no additional meaning beyond implying the parameter specifies minutes until pausing, which is already covered. With high schema coverage, the baseline score of 3 is appropriate as the description does not compensate but also does not detract.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the specific action ('Set a sleep timer') and the resource/outcome ('to automatically pause playback after specified minutes'). It distinguishes itself from siblings like 'cancel_sleep_timer' (which stops a timer) and 'control_playback' (which handles general playback control), making the purpose unambiguous.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description provides no guidance on when to use this tool versus alternatives. It does not mention prerequisites (e.g., whether playback must be active), exclusions (e.g., if multiple timers can be set), or comparisons to siblings like 'cancel_sleep_timer' for stopping timers or 'control_playback' for manual pausing, leaving usage context unclear.

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

• control_playbackA
  3.5/5.0
  Behavior3/5

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

  With no annotations provided, the description carries the full burden of behavioral disclosure. It adds important context about the skip behavior limitation ('will only skip once per call'), which isn't obvious from the schema alone. However, it doesn't disclose other behavioral traits like whether this requires authentication, rate limits, what happens if no device is specified, or error conditions. The description doesn't contradict any annotations since none exist.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is perfectly concise - two sentences that each earn their place. The first sentence states the core purpose, the second adds crucial behavioral context about skip limitations. No wasted words, front-loaded with the essential information. The structure is logical and efficient.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness3/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  For a playback control tool with 3 parameters, 100% schema coverage, but no annotations or output schema, the description is minimally adequate. It covers the basic purpose and one important behavioral constraint, but doesn't address authentication needs, error handling, what happens when no device is specified, or return values. Given the complexity of media playback control, more context would be helpful for an agent to use this tool effectively.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  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 all parameters thoroughly. The description adds minimal value beyond the schema - it mentions the same actions and volume control but doesn't provide additional semantic context. The note about skip behavior relates to parameter usage but doesn't add meaning to the parameters themselves. With high schema coverage, baseline 3 is appropriate.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose4/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the tool's purpose: 'Control Spotify playback (play, pause, skip, volume)' - a specific verb (control) and resource (Spotify playback). It distinguishes itself from siblings like play_album or play_track by focusing on playback control rather than content selection. However, it doesn't explicitly contrast with all relevant siblings like set_sleep_timer or get_current_playing.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines3/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description provides implied usage guidance through the note about skip behavior ('skip-next and skip-previous will only skip once per call'), which suggests when to use this tool versus making multiple calls. However, it doesn't explicitly state when to use this versus alternatives like play_track for starting playback or set_sleep_timer for timed control. No explicit exclusions or comparisons with sibling tools are provided.

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

• get_devicesA
  3.9/5.0
  Behavior2/5

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

  No annotations are provided, so the description carries the full burden of behavioral disclosure. It states what the tool does but lacks details on permissions needed, rate limits, response format, or whether it requires authentication. For a tool with zero annotation coverage, this is a significant gap in transparency.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is a single, efficient sentence that front-loads the core purpose without unnecessary words. Every part of the sentence contributes directly to understanding the tool's function, making it optimally concise and well-structured.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness3/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given the tool's complexity (simple read operation with no parameters) and lack of annotations and output schema, the description is minimally complete. It states what the tool does but does not cover behavioral aspects like response format or error handling, which could be helpful for an agent. It meets basic adequacy but has clear gaps.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters4/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  The tool has 0 parameters with 100% schema description coverage, so no parameter documentation is needed. The description does not add parameter semantics, but this is appropriate given the lack of parameters, warranting a baseline score of 4 for adequately handling the parameter-free context.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the verb ('Get') and resource ('list of available Spotify devices and the current default device'), making the purpose specific and unambiguous. It distinguishes from siblings like 'set_default_device' (which sets rather than gets) and 'control_playback' (which controls rather than lists devices).

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines4/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description implies usage context by specifying what it retrieves (available devices and default device), suggesting it should be used when device information is needed. However, it does not explicitly state when to use this tool versus alternatives like 'set_default_device' or provide exclusion criteria, leaving some guidance gaps.

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