jaeger-mcp

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

The annotations already provide readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true. The description adds valuable behavioral context beyond annotations: it mentions that the output is capped at 500 services with a truncation hint, that Jaeger returns all services at once with no pagination, and that it wraps GET /api/services. This provides important operational details not covered by annotations.

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

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

The description is well-structured with clear sections: purpose statement, implementation details, usage guidance with examples, and return format. Every sentence adds value - there's no redundancy or filler. The information is front-loaded with the core purpose stated first.

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

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

Given the tool has 0 parameters, comprehensive annotations, and an output schema (implied by the Returns section), the description provides complete contextual information. It covers purpose, behavioral characteristics, usage scenarios with examples, and return format - everything needed for an agent to understand and use this tool effectively.

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

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

With 0 parameters and 100% schema description coverage, the baseline would be 4. The description explicitly states 'call with no parameters' and provides examples of usage without parameters, which reinforces the parameterless nature of this tool. This adds clarity beyond what the empty schema alone conveys.

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

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

The description clearly states the specific action ('List all services that Jaeger has observed traces for') and distinguishes it from sibling tools by mentioning it's the first step before calling jaeger_list_operations or jaeger_search_traces. It provides a precise verb+resource combination with clear scope.

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

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

The description provides explicit guidance on when to use this tool (e.g., 'What services does Jaeger know about?', 'Is `payment-service` instrumented?', 'Starting a debugging session') and when not to use it (e.g., 'Don't use when: You already know the service name and want to search its traces', 'Don't use when: You want the dependency graph between services'). It names specific alternative tools for different scenarios.

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