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, so the safety profile is fully covered. The description adds 'field by field, with sources', a useful hint about comparison granularity and provenance, but says nothing about output shape, limits on which tools can be compared, or failure behavior.

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 tight sentence with the verb and scope front-loaded and zero filler. The terseness is efficient rather than repetitive, though it leaves the definition thin overall.

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?

There is no output schema, so the description must carry the return-value burden; 'field by field, with sources' gestures at it but does not describe the structure. Combined with undocumented slug parameters and no usage routing versus get_tool, this is minimum-viable rather than complete.

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% for both required parameters, and the description does not compensate: it never explains what a 'slug' is, how to obtain one, or whether the two slugs must differ. The term 'slug' is the only implicit semantic hint.

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 verb ('compare') plus resource ('two tools'), with scope qualifiers 'side by side, field by field, with sources'. This is distinct from its siblings (get_tool, search_tools, list_category), but the description never names or contrasts them explicitly.

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?

No statement of when to prefer this over calling get_tool twice, nor any prerequisites for the comparison. The usage is only implied by the verb 'compare'.

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