List Tool Packages

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

Annotations already provide readOnlyHint=true and openWorldHint=true, covering safety and dynamic results. The description adds useful context about session filtering and package existence, which helps the agent interpret the output. No contradictions or hidden side effects are implied.

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?

Two concise sentences: the first states the function and scope, the second adds a valuable usage note. Information is front-loaded and every word earns its place.

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 no-parameter, read-only introspection tool, the description fully covers what it does, when to use it, and how to interpret results. Annotations handle safety and open-world aspects, and no return format is needed for a simple list view.

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 tool has zero parameters and 100% schema coverage, so the baseline is 4. The description introduces no parameter details, but none are needed. It focuses on the tool's purpose and usage context, which is appropriate.

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 uses a specific verb ('Show') with a clear resource ('which tool package this session is running and what other packages exist'). It distinguishes this tool from the many sibling data-manipulation tools by focusing on package inventory rather than records or operations.

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 explicitly states when to use the tool: when a capability is missing, suggesting the tool may exist but is filtered out. It clarifies the expected interpretation (a different MCP_TOOL_PACKAGE) and prevents confusion with a missing feature. This is strong actionable guidance.

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