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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds only one behavioral detail beyond that — results are 'with sources' — but says nothing about return format, ordering, or behavior when a slug is invalid.

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?

A single front-loaded sentence that packs the action and three scope qualifiers with no filler. Nothing could be removed without losing meaning.

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 two-parameter comparison tool with no output schema, the description needs to carry more weight on identifier semantics and result shape. It is adequate for an agent that already knows the slug convention but leaves real gaps for one that does not.

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 0% and neither slug_a nor slug_b is described anywhere. 'Two tools' weakly implies each slug identifies a tool, but the description gives no format, source, or constraint (e.g., where a slug comes from, whether both must exist), so the parameters remain ambiguous.

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?

Clear specific verb 'Compare' plus resource 'two tools', with useful scope detail ('side by side, field by field, with sources'). It distinguishes itself from get_tool/list_category by the pairwise comparison framing, though it never names a sibling to reinforce the contrast.

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 never says when to prefer it over get_tool (single lookup) or search_tools (discovery). No prerequisites, no when-not conditions, and no routing hint are given; the agent must infer usage from the name alone.

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