Joomil — Swiss Classifieds MCP

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows this is a safe read operation. The description adds valuable context about the return format ('flat list with parent_id for hierarchy reconstruction') and the active status filtering ('active categories'), which goes beyond what annotations provide.

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 perfectly concise with three sentences that each serve a distinct purpose: stating the core function, describing the return format, and providing usage guidance. Every word earns its place with zero waste.

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

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

For a simple read operation with good annotations and full schema coverage, the description provides exactly what's needed: clear purpose, return format explanation, and parameter usage guidance. The lack of output schema is compensated by the description of what's returned.

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

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

Schema description coverage is 100%, so the schema already fully documents the parent_id parameter. The description repeats the same information about when to omit, use 0, or use specific IDs, but doesn't add meaningful semantic context beyond what's in the schema.

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 active categories'), identifies the resource ('Joomil.ch marketplace'), and distinguishes the scope ('flat list with parent_id for hierarchy reconstruction'). It provides a complete picture of what the tool does beyond just the name.

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

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

The description provides explicit guidance on when to use different parameter values: 'Omit parent_id for all categories, use parent_id=0 for root categories only, or pass a specific ID to get direct children of that category.' This gives clear alternatives for different filtering scenarios.

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

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

Annotations already declare readOnlyHint=true and destructiveHint=false, indicating a safe read operation. The description adds valuable context beyond this by specifying what data is returned (description, images, category, vendor info, expiry, boost level) and the source (Joomil.ch), which helps the agent understand the tool's behavior and output format. No contradictions with 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 efficiently structured in two sentences: the first states the purpose and output details, the second provides usage guidance. Every sentence adds critical information without redundancy, making it front-loaded and zero-waste.

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's low complexity (1 parameter, no output schema), the description is highly complete. It covers purpose, usage guidelines, and output details, compensating for the lack of output schema. However, it doesn't mention potential errors or edge cases (e.g., invalid ID handling), leaving a minor gap.

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

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

The input schema has 100% description coverage, fully documenting the 'id' parameter. The description adds minimal semantic value beyond the schema by mentioning 'numeric ID' and referencing 'search_classifieds results,' but doesn't provide additional syntax or format details. 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.

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

The description clearly states the specific action ('Get full details'), resource ('a single classified ad on Joomil.ch'), and scope ('by its numeric ID'). It distinguishes from sibling tools by explicitly mentioning 'search_classifieds' as the method to find IDs, making the purpose unambiguous and distinct.

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 vs. alternatives: 'Use search_classifieds first to find relevant listing IDs.' This clearly indicates the prerequisite step and differentiates it from the sibling tool, offering complete context for proper tool selection.

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

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

The description adds valuable behavioral context beyond what annotations provide. While annotations declare readOnlyHint=true and destructiveHint=false (indicating a safe read operation), the description specifies that results are 'paginated,' that descriptions are 'truncated to 300 chars,' and that it returns 'public listings' with specific fields. This provides important implementation details that help the agent understand what to expect from the tool's behavior.

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

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

The description is perfectly structured and concise with zero wasted words. The first sentence establishes purpose and context, the second describes the return format, the third explains parameter flexibility, and the fourth provides sibling tool guidance. Every sentence earns its place and information is front-loaded appropriately.

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

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

For a search tool with good annotations (readOnlyHint=true, destructiveHint=false) and comprehensive parameter documentation (100% schema coverage), the description provides excellent contextual completeness. It explains the tool's scope, return format, parameter flexibility, and relationship to sibling tools. The only minor gap is the lack of an output schema, but the description adequately describes the return format to compensate.

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 100% schema description coverage, the input schema already documents all 9 parameters thoroughly. The description doesn't add significant parameter-specific information beyond what's in the schema, though it does provide the helpful context that 'All parameters are optional — call with no arguments to browse the latest listings,' which helps interpret the parameter semantics at a high level.

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 ('Search classified ads'), identifies the target resource ('on Joomil.ch'), and distinguishes it from sibling tools by explicitly mentioning 'Use get_classified to fetch full details of a specific listing.' This provides clear differentiation from both get_categories and get_classified.

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 vs alternatives: 'Use get_classified to fetch full details of a specific listing.' It also provides context about when to use this tool alone: 'All parameters are optional — call with no arguments to browse the latest listings.' This gives clear direction for both the primary use case and alternative scenarios.

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