Serena MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool 'Activates' modes, implying a state change, but doesn't describe what activation entails (e.g., immediate effect, persistence, side effects), permissions required, or error conditions. This is insufficient for a mutation tool with zero annotation coverage.

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

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

The description is a single, efficient sentence that front-loads the core action ('Activates') and includes illustrative examples. There is no wasted text, making it easy to parse and understand quickly.

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 complexity of a mode-switching tool with no annotations and no output schema, the description is incomplete. It lacks details on behavioral traits (e.g., what activation does, side effects), usage context, and return values, leaving significant gaps for the agent to operate 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?

Schema description coverage is 100%, with the parameter 'modes' clearly documented as an array of strings for mode names. The description adds value by providing examples like ['editing', 'interactive'] or ['planning', 'one-shot'], which clarify the expected format and possible values, but doesn't go beyond what the schema already covers in terms of semantics.

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 action ('Activates') and the target ('desired modes'), with specific examples provided. However, it doesn't explicitly differentiate this tool from potential sibling tools that might also manage modes or configurations, such as 'get_current_config' or 'restart_language_server', leaving some ambiguity about its unique role.

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 no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites, context for activation, or how it relates to other tools like 'get_current_config' or 'restart_language_server', which could involve mode changes. This lack of usage context leaves the agent without clear direction.

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