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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, covering the safety profile. The description adds useful context: 'Takes no parameters and requires no authentication.' However, it does not describe the return format or any other behavioral traits beyond what annotations provide. A 3 is appropriate given the lower bar 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?

Two tightly written sentences with the core purpose front-loaded. Every sentence earns its place: the first defines the lookup and its scope, the second clarifies no parameters and no authentication. No waste or redundancy.

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 parameterless lookup with rich annotations and no output schema, the description is nearly complete. It states that the return is a 'complete migration matrix' but does not detail its structure or contents, which is a minor gap. The no-auth and no-params statements round out the call context well.

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, so the baseline is 4. The description explicitly confirms 'Takes no parameters', which aligns with the empty schema and reinforces that no input is needed. No further parameter semantics are required.

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 ('lookup') and a well-defined resource ('migration matrix for archived or frozen @modelcontextprotocol/server-* reference packages and their official 2026 vendor-maintained replacements'). It does not explicitly name or differentiate from siblings like check_stack_drift, but the domain is distinct enough that an agent can infer the difference. Score 4 because sibling differentiation is absent.

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 states what the tool does but gives no guidance on when to use it versus alternatives such as check_stack_drift or get_package_stability. It also provides no exclusions or preconditions beyond 'requires no authentication'. An agent must infer the use case from the purpose statement alone.

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