Haloscan MCP Server

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. 'Définir' implies a mutation/write operation, but the description doesn't specify whether this persists across sessions, what permissions are required, whether it overwrites existing keys, or what happens on success/failure. For a configuration tool with zero annotation coverage, this leaves critical behavioral questions unanswered.

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 extremely concise at just three words, with no wasted language. However, this brevity comes at the cost of under-specification - it's so minimal that it fails to provide adequate context. Still, as a standalone statement, it's efficiently structured.

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 configuration tool with no annotations and no output schema, the description is inadequate. It doesn't explain what system this configures, whether the change is persistent, what happens on success, or any error conditions. Given this tool's apparent role as the only configuration mechanism among many data retrieval siblings, the description should provide more complete context about its purpose and behavior.

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, with the single parameter 'apiKey' clearly documented as 'Your Haloscan API key'. The description adds no additional parameter information beyond what the schema provides. With complete schema coverage, the baseline score of 3 is appropriate since the schema already does the heavy lifting.

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 'Définir la clé API' is a tautology that essentially restates the tool name 'set_api_key' in French. It doesn't specify what resource or system this API key is for, nor does it distinguish this tool from any potential alternatives. While it indicates an action ('définir' meaning 'set'), it lacks specificity about what exactly is being configured.

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 absolutely no guidance on when to use this tool versus alternatives. Given the sibling tools are all 'get_' operations for data retrieval, this appears to be the only configuration tool, but the description doesn't mention this distinction, prerequisites for use, or any contextual triggers for when this operation is needed.

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