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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the description only needs to add context. It does: 'Free: no lookup is spent' discloses a cost/quota trait that annotations cannot express, and '50 vendors a page' discloses pagination granularity. It does not explain cursor semantics or ordering, keeping it out of the top band.

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 short sentences, zero filler, with the core verb/resource/filter front-loaded and the cost and pagination notes following in decreasing priority. Every sentence earns its place.

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 list tool with no output schema, the description covers the filter semantics, the cost model, page size, and the natural next call, which is most of what an agent needs. It omits result ordering and what happens when the portfolio has no changes, minor gaps rather than blocking ones.

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%, so both parameters are already documented in the schema; the description's 'on or after a date' merely restates the since parameter's own wording. The page-size note is useful context but does not clarify how cursor should be obtained or used. Baseline 3 applies when the schema carries the parameter burden.

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?

States a specific verb and resource ('List the vendors in your VendorWatch portfolio') with an explicit filter scope ('whose record changed on or after a date'), and enumerates what counts as a change (profile updated, DPA analysed, DPA document changed). This lets an agent distinguish it from get_vendor_profile (single record) and find_vendor (lookup) without opening any schema.

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 a clear usage context (free, no lookup is spent) and names the follow-on tool with its purpose ('read the new profile with get_vendor_profile'), which is real routing guidance. It stops short of stating when NOT to use this tool versus check_portfolio or find_vendor, so it falls below the explicit when/when-not bar.

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