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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuinely new behavior: auto-selection of comparable projects by theme similarity, and that results are headlines plus shared and divergent themes.

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?

Three tight sentences, action first, then the two modes, then the return shape. Every sentence carries information an agent needs and there is no filler.

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?

An output schema exists, so return values need not be detailed, and annotations carry the safety profile. The description covers both invocation paths and the general result content, leaving nothing material for an agent to guess.

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 coverage is 100% (including maxProjects' default of 3), so baseline is 3. The description adds the '2+' minimum for explicit comparison, a constraint the schema does not state, plus a plain-language restatement of the null/one auto-find behavior.

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?

Specific verb+resource ('Compare feedback across projects') that is easy to distinguish from generic listing tools. It clearly explains the two operating modes, though it never names the nearest sibling (similar_projects), which is the one an agent might confuse it with.

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?

Gives explicit invocation conditions: pass 2+ projectIds to compare those explicitly, or a single/none to trigger theme-similarity auto-discovery. That is clear when-to-use guidance, but it offers no exclusions or named alternatives, so it stops short of a 5.

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