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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety and repeatability profile is covered structurally. The description adds which dimensions are compared, but says nothing about behavior for an unknown or duplicate slug, result ordering, or partial failures — useful additions that are absent.

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?

One front-loaded sentence: the operation, the cardinality constraint, and the compared attributes all arrive in order with zero filler. Nothing could be removed without losing signal.

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 single-parameter, read-only, closed-world tool with full schema coverage and no output schema, the description is largely sufficient — it even previews the compared fields. Minor gaps remain around slug sourcing and error behavior, but nothing blocks a correct call.

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% and the single parameter's minItems/maxItems bounds are already encoded in the schema. The description restates '2 to 5 projects by slug' without adding slug format, source, or discovery guidance (e.g., obtainable via search_projects), so the baseline 3 applies.

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?

Names a specific verb and resource ('Side-by-side comparison of 2 to 5 projects by slug') and enumerates the compared attributes, so an agent can distinguish this batch-comparison tool from get_project and search_projects without opening the schema. It stops short of naming those siblings explicitly, which keeps it from a 5.

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 2-to-5-project framing implies the comparative use case, but there is no explicit 'use this when comparing, use get_project for a single project' guidance and no stated exclusions. The agent must infer the routing decision from the phrasing alone.

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