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

Annotations already declare read-only, idempotent, non-destructive behavior, and the description goes well beyond that with operational caveats: the 90-day clamp, the asOf lag meaning 'no changes' is relative to asOf not now, omission of repeated unchanged captures, and truncation flags (truncated/toolsTruncated) that must be checked before trusting completeness.

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?

Front-loaded with the purpose and the routing hint, then the caveats, so an agent gets the essentials immediately. It is a dense single block of roughly 150 words, and while nearly every sentence carries operational information, tight formatting into distinct caveat lines would read better.

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?

With an output schema present the description needn't explain return values, yet it still covers the failure modes an agent must handle (asOf lag, 90-day clamp, truncation flags). For a read-only digest tool with full schema coverage, nothing needed to invoke or interpret it correctly is missing.

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%, so the baseline is 3, but the description adds real meaning beyond the schema: include_contract_changes is explained as pulling MCP contract baselines grouped by description/input/output schema with Version links, and it clarifies that baselines are first-known contracts, not tool additions.

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 ('Summarize what changed in a Flowlines namespace since a timestamp') and enumerates the contents of the digest: session activity/outcomes, signals fired, notes pinned. It also positions itself against the family of list_* siblings by framing the tool as a substitute for 'composing several list calls'.

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?

Explicitly says to use it for 'what's new since I last looked' instead of composing several list calls, which is a clear trigger plus a named alternative pattern. There is no explicit when-not condition (e.g. when to prefer get_namespace_overview or the individual list_* calls instead), so it stops just short of the top band.

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