javaperf

by theSharque

Overview Schema Related Servers Score Discussions

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Server Quality Checklist

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Latest release: v1.4.1
Disambiguation5/5
Each tool targets a specific aspect of Java performance profiling (thread analysis, deadlock, GC, heap, JFR, various profiles). Descriptions clearly differentiate them, even where functionality might seem similar (e.g., analyze_threads vs check_deadlock, heap_histogram vs heap_live_histogram_diff).
Naming Consistency5/5
All tool names use consistent snake_case with a verb_noun pattern (e.g., list_java_processes, start_profiling, profile_time). The naming is predictable and adheres to a single convention throughout.
Tool Count4/5
26 tools is slightly above the typical 3-15 range but well-justified for the comprehensive domain of Java performance analysis. Each tool serves a distinct purpose, and the count reflects the complexity of the subject without being excessive.
Completeness5/5
The toolset covers the full lifecycle of performance profiling: discovery, starting/stopping recordings, analyzing CPU, memory, I/O, locks, network, and interpreting results. There are no obvious gaps for local Java process analysis, making it a complete toolkit.
Average 3.9/5 across 26 of 26 tools scored. Lowest: 2.6/5.
See the Tool Scores section below for per-tool breakdowns.
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This repository is licensed under MIT License.
This repository includes a README.md file.
No tool usage detected in the last 30 days. Usage tracking helps demonstrate server value.
Tip: use the "Try in Browser" feature on the server page to seed initial usage.
Add a glama.json file to provide metadata about your server.
If you are the author, simply .
If the server belongs to an organization, first add glama.json to the root of your repository:
```
{
  "$schema": "https://glama.ai/mcp/schemas/server.json",
  "maintainers": [
    "your-github-username"
  ]
}
```
Then . Browse examples.
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How is the quality score calculated?

The overall quality score combines two components: Tool Definition Quality (70%) and Server Coherence (30%).

Tool Definition Quality measures how well each tool describes itself to AI agents. Every tool is scored 1–5 across six dimensions: Purpose Clarity (25%), Usage Guidelines (20%), Behavioral Transparency (20%), Parameter Semantics (15%), Conciseness & Structure (10%), and Contextual Completeness (10%). The server-level definition quality score is calculated as 60% mean TDQS + 40% minimum TDQS, so a single poorly described tool pulls the score down.

Server Coherence evaluates how well the tools work together as a set, scoring four dimensions equally: Disambiguation (can agents tell tools apart?), Naming Consistency, Tool Count Appropriateness, and Completeness (are there gaps in the tool surface?).

Tiers are derived from the overall score: A (≥3.5), B (≥3.0), C (≥2.0), D (≥1.0), F (<1.0). B and above is considered passing.

Tool Scores

Behavior2/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It only says 'code heap usage and related JVM output', omitting details like read-only nature, required JVM state, or error handling.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Conciseness4/5
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence that efficiently states the purpose. It is front-loaded and concise, but additional context could be added without harming 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?
Given the simple schema and no output schema, the description could still provide more complete context, such as expected output format or prerequisites, which is missing.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Parameters1/5
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The parameter 'pid' has no schema description (0% coverage) and the tool description does not mention it. The description fails to clarify what pid is or how it should be used.
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 shows code heap usage and related JVM output, effectively communicating the resource and action. However, it could be more specific about what 'related JVM output' includes.
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 heap_histogram or gc_class_stats. No context on prerequisites or scenarios is given.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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 mentions 'diagnostics' but does not disclose whether the operation is read-only, requires special permissions, or what side effects (if any) occur. For a diagnostic command, this is insufficient.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Conciseness4/5
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is extremely concise (12 words), which is efficient, but it sacrifices necessary detail. It is front-loaded with the command name and purpose, but lacks structure or additional context.
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 simplicity (one parameter, no output schema), the description should at least specify what diagnostics are provided (e.g., number of finalizable objects, queue length). It fails to do so, leaving the agent to guess the return value and behavior.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Parameters1/5
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema has 0% parameter description coverage, and the description does not explain the 'pid' parameter at all. The description adds no semantic meaning beyond the schema, which is critical since the schema provides no description.
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 identifies the tool's purpose as finalizer queue diagnostics using 'jcmd GC.finalizer_info'. It specifies the resource (finalizer queue) and action (diagnostics), distinguishing it from siblings like gc_class_stats which focus on class statistics.
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. Sibling tools exist (e.g., gc_efficiency, heap_histogram) but there is no mention of conditions or exclusions, leaving the agent without context for selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior2/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, and the description does not disclose if the operation is read-only, requires specific permissions, or has side effects. Only the core functionality is stated.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Conciseness3/5
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is one short sentence, which is concise but under-specifies the tool. It is front-loaded but too minimal.
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?
With one required parameter, no output schema, and no parameter descriptions, the description is incomplete for an agent to correctly invoke the tool. More context on expected output and prerequisites is needed.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Parameters2/5
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0%, and the description adds no meaning to the 'pid' parameter beyond the schema. It should explain that pid is a Java process ID.
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 'methods queued for JIT compilation' clearly identifies the resource and action (listing queued JIT methods), and distinguishes it from sibling tools like compiler_codecache.
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 on when to use this tool vs alternatives like compiler_codecache or trace_method. The context of 25 sibling tools necessitates such guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior2/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must fully convey behavioral traits. It mentions the requirement for NativeMethodSample but does not disclose whether the tool is read-only, its performance impact, or any side effects.
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 two sentences with no redundant words. It front-loads the core purpose and adds a critical prerequisite efficiently.
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 simple tool with two parameters and no output schema, the description covers the core function and a key prerequisite. However, it lacks context on when to choose this over related profiling tools and what the output contains.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Parameters1/5
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The description does not explain the parameters (filepath, topN) or their purpose. With 0% schema description coverage, the agent receives no guidance on parameter meaning beyond defaults and constraints.
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 tool profiles 'CPU-style cumulative hotspots from jdk.NativeMethodSample stacks,' which is specific and distinct from sibling tools like profile_jfr_file_io or profile_memory.
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 a key prerequisite (NativeMethodSample must be enabled, often requiring custom .jfc), but does not explicitly state when to use this tool versus alternatives like profile_jfr_file_io or profile_memory.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior2/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must disclose behavioral traits. It only mentions the need to enable events via custom .jfc, but does not specify whether the tool is read-only, destructive, or has other side effects. This is minimal transparency.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Conciseness4/5
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is concise with three sentences that pack relevant information. It could be slightly more structured (e.g., bullet points) but avoids unnecessary words.
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 complexity of lock profiling and the number of sibling tools, the description covers the main purpose and related tools. However, it lacks explanation of return values or output format, and parameter details are missing. It is adequate but not thorough.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Parameters2/5
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema has 0% description coverage, and the tool description does not explain the parameters (filepath, topN) beyond their schema defaults. It adds no meaning to what filepath represents or how topN affects output, leaving the agent to infer from names.
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 tool's purpose: profiling lock contention from JFR, specifying two types (synchronized monitors and parking). It distinguishes itself from sibling tools by referencing analyze_threads and check_deadlock for related but different tasks.
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 provides guidance on when to use this tool versus alternatives: for live wait chains, use analyze_threads; for deadlocks, use check_deadlock. It also hints at prerequisites (enabling JFR events). However, it does not explicitly state when not to use this tool or cover all alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior2/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full responsibility. It does not disclose whether the operation is read-only, requires permissions, or any side effects. The phrase 'quick snapshot' hints at non-destructiveness, but this is insufficient.
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?
A single concise sentence that front-loads the key information (brief heap usage summary) and includes distinguishing detail ('without full dump'). No unnecessary words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity (single parameter, no output schema, no nested objects), the description adequately hints at the output (capacities, used, committed). It provides enough for a quick snapshot context, though more detail on return format would improve completeness.
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 coverage is 100%, with the parameter 'pid' already described in the schema as a required integer. The description adds no further parameter semantics beyond the schema's existing explanation.
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 tool provides a 'brief heap usage summary' covering capacities, used, and committed regions. It distinguishes itself from a 'full dump', making its purpose specific and unambiguous.
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 implies use for a quick overview ('quick snapshot without full dump') but does not explicitly state when to use this tool over sibling tools like heap_dump or heap_histogram. No exclusion criteria or alternative suggestions are given.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior3/5
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 discloses the prerequisite and behavior when prerequisite is not met. However, it does not describe side effects (e.g., performance impact) or the format of the output, which are important for an AI agent assessing execution safety.
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?
Single sentence that is clear, direct, and informative. No redundant words. It front-loads the key action and prerequisite efficiently.
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 low complexity (single required parameter, no output schema), the description covers the basic action and prerequisite. However, it lacks details on the return value (e.g., what the summary contains) and potential issues (e.g., permission requirements). An agent might struggle to interpret the expected output.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Parameters1/5
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema has one parameter 'pid' with 0% description coverage. The description does not explain what 'pid' represents or how to obtain it, nor does it add any semantic meaning beyond the schema. This is a significant gap for an AI agent to correctly invoke the tool.
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?
Description clearly states it runs 'jcmd VM.native_memory summary=true' and specifies the prerequisite (JVM started with -XX:NativeMemoryTracking). The verb 'summary' combined with 'native_memory' and the exact command distinguishes it from sibling tools like 'heap_dump' or 'gc_class_stats'.
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?
Explicitly mentions the required JVM flag and states that if not enabled, it explains how to enable. This gives clear context on when to use the tool. However, it does not explicitly mention alternatives or when not to use it, but given the unique nature among siblings, this is sufficient.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior3/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must carry the full burden of behavioral disclosure. It describes the analysis performed (pause time vs freed bytes) but does not state whether the tool modifies the .jfr file, requires any permissions, or has side effects. Since the tool is likely read-only and safe, the omission is minor but not ideal.
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?
Three concise sentences: purpose, usage context, and sibling differentiation. No redundant or verbose language. Front-loaded with the core function.
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?
The description is adequate but not complete. It defines the output (GC efficiency metrics) and usage sequence, but lacks parameter documentation. Given the tool has only two optional parameters with defaults, the missing parameter info is a notable gap. The sibling references provide good context.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Parameters1/5
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The schema has 0% description coverage, meaning parameters are not documented in the schema. The description does not mention filepath or topN at all, leaving their purpose and usage entirely unexplained. The default values and constraints in the schema are insufficient for an agent to understand how to use them correctly.
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 tool extracts GC efficiency metrics (pause time vs freed bytes) from .jfr files, broken down by collector/cause. It explicitly distinguishes itself from parse_jfr_summary, a sibling tool for general JFR summaries, and positions itself as complementary to profile_memory and heap_info.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Usage Guidelines5/5
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives explicit usage context: use after stop_profiling, complements profile_memory and heap_info, and refers to parse_jfr_summary as the alternative for a general JFR summary. This provides clear when-to-use and when-not-to-use guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior3/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description discloses that the tool is for profiling (not mutation) and clarifies that OldObjectSample is by allocation site, not GC roots. But it omits details on rate limits, idempotency, or authorization needs.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Conciseness4/5
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two sentences, efficiently stating the tool's purpose and usage context with pairing and prerequisites. Slightly more structure could be beneficial, but it's well front-loaded.
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 (allocation stacks, OldObjectSample) and lack of output schema, the description provides a solid conceptual overview but leaves detailed output format unexplained. It suffices for understanding the tool's role within the sibling set.
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 coverage is 100%, so baseline is 3. The description repeats the concept of top allocators by bytes/count but adds no new parameter details beyond what the schema already provides in parameter descriptions.
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 tool provides JFR memory profile data including top allocators and allocation stacks, and distinguishes from siblings like heap_dump and heap_live_histogram_diff by pairing suggestions.
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 provides pairing suggestions with specific sibling tools and notes the prerequisite of a profile preset recording, offering clear context for usage. However, it lacks explicit when-not-to-use guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior3/5
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 the tool returns JVM information, but does not disclose behavioral traits like side effects, permissions, or limitations. For a read-only info tool, it is minimally adequate.
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 sentence that efficiently conveys the purpose and content, with no redundant or extraneous information.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the simplicity of the tool (single parameter, no output schema), the description provides a reasonably complete overview of what it does. However, it lacks details about the return format or structure, which would be helpful but not critical.
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 coverage is 100% with the 'pid' parameter already described as 'Process ID of the Java application. Get this from list_java_processes.' The description adds no extra semantic meaning beyond the schema, so baseline score of 3 applies.
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 tool returns JVM uptime, version, and flags, with a specific use case of environment verification. This distinguishes it from sibling diagnostic tools.
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 mentions the tool is 'useful for environment verification,' implying a context, but does not provide explicit when-to-use or when-not-to-use guidance, nor alternatives among siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior3/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must disclose behavior. It indicates a non-destructive read operation ('Checks') and explains the internal mechanism (parsing jcmd Thread.print), but omits details on permissions or rate limits. Adequate but not exhaustive.
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 two sentences: the first defines the primary action, the second expands on output and usage. No unnecessary words, front-loaded with key information.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple tool with one parameter and no output schema, the description adequately covers purpose, internal mechanism, output structure, and use case. It could include more detail on required permissions or exact output fields, but it is sufficient for an AI to understand the tool's role.
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 coverage is 100%, and the schema already describes the 'pid' parameter as a process ID from 'list_java_processes'. The description adds no further parameter meaning beyond this, so baseline score of 3 is appropriate.
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 'Checks' and the resource 'Java-level deadlocks in the specified process'. It also details the output, distinguishing it from sibling tools like 'analyze_threads' which might cover broader thread analysis.
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 provides usage context via 'Use for automated analysis and reports', implying when to use. However, it does not explicitly mention when not to use or compare to alternatives like 'analyze_threads'.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior3/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided, so description must cover behavior. Lists output components but does not disclose whether tool is destructive, requires permissions, or has performance implications. Since it's a parser, read-only is implied but not confirmed.
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?
Two sentences, no fluff. Front-loaded with purpose and output, then usage guidance. Each sentence earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With 3 optional parameters and no output schema, the description gives a solid overview of what to expect. It could mention the output format or that it's a lightweight summary, but it's sufficient for quick understanding.
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 coverage is 100%, so baseline 3. Description adds minimal extra meaning beyond schema; does not explain how 'events' parameter affects output or the structure of 'topN' results.
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?
Clearly states verb (parse), resource (.jfr file), and specific output elements (top methods by CPU, GC stats, thread allocation, anomaly hints). Differentiates from sibling tools like heap_dump or gc_efficiency by emphasizing high-level overview.
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?
Explicitly says 'Use for a quick high-level overview before diving into specific profiles,' providing clear context. However, it does not explicitly name alternative tools or state when not to use it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior3/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It implies read-only behavior but does not explicitly state non-destructiveness or other traits beyond preconditions.
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?
Two sentences clearly conveying purpose and usage without any wasted words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no output schema and no annotations, the description adequately covers purpose, preconditions, and parameters. Could mention output format but not necessary for clarity.
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 coverage is 100%, and the description echoes 'top paths' matching topN. It adds no additional meaning beyond the schema definitions.
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 specifies the tool summarizes file read/write events (jdk.FileRead, jdk.FileWrite) with counts, bytes, top paths, and stack hotspots, clearly distinguishing it from sibling tools that profile other aspects like locks or network.
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?
It states events must exist in the recording and mentions configuration via start_profiling preset or settingsFile, giving clear context. However, it does not explicitly mention when not to use or compare directly to alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior2/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Without annotations, the description must fully disclose behavior. It mentions stopping and saving but does not indicate whether it overwrites existing files, requires specific permissions, or behaves differently if no active recording exists. This lacks depth 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?
Two sentences, front-loaded with the main action. No unnecessary words, every sentence contributes to clarity. Exemplary conciseness.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description is adequate for a simple stop command with well-defined parameters. It explains the output file usage. However, it lacks error handling details and return value explanation, which is acceptable since no output schema exists and the task is straightforward.
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 input schema covers both parameters with descriptions (100% coverage). The description adds value by linking pid and recordingId to the start_profiling tool, ensuring consistency. This extra context improves parameter semantics beyond the schema.
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 tool stops an active JFR recording and saves it to a specific file, with a distinction between new and old files for before/after comparison. It uniquely identifies the tool among siblings like start_profiling and list_jfr_recordings.
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 explains how to use the output files (new vs old) for comparison, but does not explicitly state when to use this tool over siblings. The context is clear, but no exclusions or alternatives are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior3/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must cover behavioral traits. It implies a read-only analysis but does not explicitly state that no modifications occur, nor does it address permissions or side effects. The description adds some context (e.g., top endpoints, stack hotspots) but leaves gaps in behavioral completeness.
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 concise, consisting of two sentences. The first sentence front-loads the core purpose, and the second provides a conditional hint. Every word is necessary and earns its place.
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?
With no output schema or annotations, the description should be more complete. It lacks details on return format, error handling, and does not fully explain 'emptyEvents' context. It covers the key points but leaves some gaps for a tool with this complexity.
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?
Schema coverage is 100%, so baseline is 3. The description adds value by explaining that filepath accepts shortcuts like 'new_profile' and 'old_profile', which goes beyond the schema description, and clarifies that topN is for endpoints and methods.
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 that the tool summarizes JDK socket I/O from .jfr files, listing specific events (jdk.SocketRead, jdk.SocketWrite) and outputs like event counts, bytes, top endpoints, and stack hotspots. This distinctly differentiates it from sibling tools like profile_jfr_file_io.
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 specifies prerequisites (recording must include events via custom .jfc or preset) and provides an alternative action (use start_profiling if emptyEvents). This gives clear when-to-use and fallback guidance, though it lacks explicit when-not-to-use compared to siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior3/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full burden. It discloses that the file is saved to a specific path and warns about large files, but does not mention whether it overwrites existing files, requires any permissions, or other side effects like performance impact.
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 three sentences long, front-loaded with the core purpose, followed by usage guidance and a warning. Every sentence adds value without redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a tool with no output schema, the description adequately explains the output (hprof file) and its typical use. It could be improved by mentioning the file size magnitude or approximate duration, but it is sufficient for an agent to understand what the tool produces.
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 input schema has 100% description coverage for the pid parameter, referencing list_java_processes. The description adds context about the tool's purpose but does not add additional meaning beyond the schema for the parameter itself.
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 tool creates .hprof files for Eclipse MAT/VisualVM and provides a specific use case after heap_live_histogram_diff, distinguishing it from sibling profiling tools by its role in the diagnostic workflow.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Usage Guidelines5/5
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives explicit guidance on when to use this tool ('after heap_live_histogram_diff picks a growing class') and includes a workflow step using MAT, along with a warning about file size. This effectively tells the agent the context and expected sequence.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior3/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided, so description carries the burden. It discloses the tool is static and uses jcmd GC.class_histogram, but does not detail other behavioral traits like performance impact or side effects.
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?
Two concise sentences, front-loaded with main purpose, then alternative. No redundant information.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Adequate for a simple tool with 3 well-documented parameters and no output schema. Clearly explains purpose and differentiation. Minor omission: no mention of return format.
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% with descriptions for all 3 parameters (pid, topN, all). The description adds no additional meaning beyond what the schema provides.
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 it provides a 'Static class histogram' using jcmd GC.class_histogram and distinguishes it from a sibling tool (heap_live_histogram_diff) for live growth analysis.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Usage Guidelines5/5
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly states when to use (for static class histogram) and when not to (for live growth, use heap_live_histogram_diff), providing a clear alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior4/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It explains the tool counts leaf methods exclusively from ExecutionSample events and returns most frequently sampled methods. This is a good disclosure, though it could mention that a .jfr file must exist and does not specify permissions or side effects.
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 concise: two sentences plus a usage hint. Every sentence provides essential information without redundancy. It is front-loaded and easy to scan.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no output schema, the description explains that methods are returned as 'most frequently sampled methods (exclusive, not cumulative).' This is mostly complete, but it doesn't specify the exact format (e.g., list with counts) or handle error conditions. Still adequate for a simple two-parameter tool.
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 coverage is 100% for both parameters (filepath, topN), and the description adds no new information beyond what the schema provides. The description mentions 'most frequently sampled methods' which relates to topN but does not elaborate further. Baseline 3 is appropriate.
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 explicitly states it produces a 'Call frequency profile from a .jfr file' and clarifies it counts leaf methods from ExecutionSample events exclusively. This clearly distinguishes it from sibling profiling tools like profile_jfr_file_io or profile_jfr_locks, which cover different aspects.
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 ends with 'Use when looking for hot spots or the most often executed code paths,' providing a clear use case. While it doesn't explicitly state when not to use it, the context from sibling tools implies alternatives for other profiling needs.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior4/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Discloses bottom-up aggregation behavior where each method is counted in every sample including callee time. No annotations provided, so description carries full burden; it provides sufficient transparency for a read-only profiling 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?
Two sentences are concise and well-structured: first defines purpose and behavior, second provides usage guidance. No redundant information.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
No output schema, but description clarifies returns methods consuming most CPU time. Lacks specifics on output format (e.g., values, sorting), but the tool's purpose is clear given context and sibling tools.
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 coverage is 100%, so description adds limited value beyond schema. It implies topN limits the number of methods returned, but doesn't provide new semantic detail beyond what the schema already states.
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?
Description clearly states the tool profiles CPU time from a .jfr file using bottom-up aggregation. It specifies the resource (.jfr file) and action (profile CPU time), distinguishing it from sibling profiling tools like profile_frequency or profile_memory.
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?
Explicitly advises use when finding performance bottlenecks and slow code paths. While it doesn't mention when not to use or list alternatives, the guidance is clear and contextually appropriate.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior4/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Describes read-only analysis of a .jfr file, filtering ExecutionSample events, and aggregating call paths. Includes a known limitation about JFR sampling frequency. Without annotations, it relies on description, which is transparent but could explicitly state no modifications are made.
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?
Three sentences succinctly cover purpose, process, use case, and limitation. Every sentence is informative and necessary. No redundant or vague phrasing.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no output schema, the description explains the tool's function and limitation. However, it does not describe the output format or type of the call tree (e.g., list of paths, percentages). Missing details on error handling or output structure slightly reduces completeness.
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?
All 5 parameters are documented in the schema (100% coverage), so baseline is 3. The description adds context about the 'events' parameter default and advanced usage, but adds little beyond the schema's own detailed descriptions. No new parameter insights beyond what schema provides.
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?
Description clearly states the tool builds a call tree for a specific method from a .jfr file, using ExecutionSample events. It specifies the verb 'traces' and resource 'method call paths', distinguishing it from sibling profiling tools that analyze threads, memory, or JFR summaries.
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?
Explicitly says 'Use when you want to see who calls a particular method and from where', providing clear usage context. It mentions a limitation (fast methods may be missed) but does not name alternative tools or give when-not-to-use guidance, though siblings offer no direct alternative for method tracing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior4/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It discloses that older JDK returns an error hint, which is a key behavioral trait. However, it does not explicitly state the tool is read-only or safe, but the context suggests it.
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?
Two concise sentences, front-loaded with the main purpose and version constraint, no wasted words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no output schema, the description covers purpose and usage well but omits details about return values or format. With a single simple parameter, this is sufficient but not exhaustive.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Parameters2/5
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 0% and the description does not mention the single 'pid' parameter. Despite its common usage, the description adds no meaning to the parameter beyond the schema.
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 tool provides GC.class_stats for class loader/metaspace stats on JDK 21+. It differentiates from siblings by specifying version support and suggesting alternatives for older JDK.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Usage Guidelines5/5
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly states when to use (JDK 21+) and when not to use (older JDK), and provides alternative tools (heap_info, heap_histogram), giving clear guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior4/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Describes the jcmd command and return fields (id, duration, state, filename). With no annotations, the description carries the burden and does so fairly well, though it omits potential errors or side effects.
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?
Two concise sentences that front-load purpose and output, with a useful usage hint. No unnecessary words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness5/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Fully covers the tool's purpose, input, output, and relationship with stop_profiling. Given the simple nature and one parameter, the description is complete.
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 coverage is 100% with a description for pid. The tool description adds no extra parameter detail beyond the schema, meeting the baseline expectation.
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?
Clearly describes listing active/recent JFR recordings, specifies return fields, and distinguishes from siblings like stop_profiling by noting its use as a prerequisite.
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?
Explicitly states to use before stop_profiling, providing clear context. Does not explicitly mention when not to use, but the guidance is sufficient for a list tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior4/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Describes rotation behavior and mutual exclusivity. With no annotations, it carries behavioral disclosure well but could mention side effects like overwriting old recordings more explicitly.
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?
Concise single paragraph packed with essential information. Every sentence adds value: core action, rotation, presets, customization, follow-up.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Covers key aspects but lacks description of return value or output. For a complex tool with no output schema, describing the result (e.g., recording ID or success status) would improve completeness.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Parameters5/5
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Adds significant value beyond 100% schema coverage: default preset, mutual exclusivity, and event limitations of builtin presets. This helps agents choose between preset and settingsFile.
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?
Clearly states it starts JFR on a target PID and rotates recordings. Differentiates from sibling tools like list_java_processes, stop_profiling, and other profiling variants.
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?
Provides guidance on using preset vs settingsFile, their mutual exclusivity, and limitations of builtin presets. Suggests follow-up steps (list_jfr_recordings, stop_profiling). Lacks explicit when-not-to-use compared to sibling profiling tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior4/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Since no annotations are provided, the description must disclose behavioral traits. It mentions the underlying command (jps -l -m), which gives transparency. It could improve by noting potential permission requirements, but overall it is sufficient for a read-only list operation.
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 two sentences with no wasted words. It front-loads the action and purpose, then provides the usage instruction. Every sentence adds value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity, the description covers purpose, return structure, usage, and underlying mechanism. It lacks details on error conditions or performance notes, but these are not critical for a diagnostic list tool.
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 single parameter topN is fully described in the schema (100% coverage). The description adds context by suggesting 'Use higher values if many Java processes are running,' providing guidance beyond the schema's default and range.
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 it lists all running Java processes and specifies the return fields (pid, mainClass, args). It distinguishes from sibling tools by explicitly positioning it as a prerequisite for profiling/analysis tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Usage Guidelines5/5
Does the description explain when to use this tool, when not to, or what alternatives exist?
Provides explicit guidance: 'Use this tool first to discover the target process PID before calling start_profiling or analyze_threads.' This clearly indicates when to use it and suggests alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior4/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
While no annotations are provided, the description discloses key behaviors: it produces a thread dump, outputs plain text by default or structured JSON for lock-wait chains (described as a 'live snapshot'), and implies it is a read-only diagnostic operation. It does not contradict any annotations (none exist) and provides sufficient behavioral context for safe invocation.
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 exceptionally concise and front-loaded: the first sentence immediately states the tool's core function ('Thread dump (jstack -l)'). Every subsequent sentence adds essential information without filler, fitting all key details into four short sentences.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness5/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Despite the absence of an output schema, the description clearly explains the two output formats (plain text and JSON with lock-wait chains) and their purposes. It also provides cross-references to related tools for related use cases, making the description self-contained and complete for an agent to 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?
Schema coverage is 100%, providing baseline descriptions for all three parameters (pid, topN, structured). The description adds value by explaining how parameters affect output (e.g., 'structured=true for JSON lock-wait chains') and giving context for pid ('Get this from list_java_processes'), going beyond what the schema alone provides.
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 it performs a thread dump (jstack -l), distinguishing between plain text and structured JSON output. It also explicitly contrasts with sibling tools for historical contention (profile_jfr_locks) and deadlock detection (check_deadlock), making its 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 Guidelines5/5
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides explicit guidance on when to use this tool (for thread dumps), when to set structured=true (for JSON lock-wait chains), and directs users to alternative tools for historical contention (profile_jfr_locks) and deadlock cycles (check_deadlock), helping agents choose correctly.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Behavior5/5
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description fully carries the burden. It warns that 'Each snapshot walks the heap and may pause the app.' and the `all` parameter description adds 'Triggers full GC and may pause the app.'
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?
Two sentences, each earning its place. First sentence states purpose and mechanism; second provides usage workflow and behavioral note. No wasted words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Completeness4/5
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a tool with 5 parameters and no output schema, the description covers core functionality, usage guidance, and disruption warnings. However, it does not detail the return format (e.g., fields per class or ordering), which could be improved.
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?
Schema description coverage is 80%, with only topN missing a description. The description implies topN limits returned classes ('...whose instance count grew most'), partially compensating. It also adds context about the `all` parameter's behavior.
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 'Two GC.class_histogram snapshots spaced by intervalSeconds; returns classes whose instance count grew most.' This provides a specific verb and resource, distinguishing it from siblings like heap_histogram (single snapshot).
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Usage Guidelines5/5
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly says 'Use first in memory-leak workflow; then profile_memory and heap_dump (MAT path-to-GC-roots).' This gives clear context and alternative tools for subsequent steps.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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