ctx_stats

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

No annotations are provided, so the description carries the full behavioral burden. It helpfully defines orphan_rate ('notes with no tags and no inbound references') and enumerates what the aggregate contains, but it never states that the operation is read-only, nor describes auth/rate-limit behavior. Decent but incomplete for an unannotated tool.

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?

Two sentences, front-loaded with the concrete output enumeration and followed by the usage statement. Every listed metric earns its place by describing the return payload. Slightly list-dense but no wasted prose.

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 no output schema, the description usefully compensates by enumerating the returned fields (totals, breakdowns, recents, orphan_rate). For a zero-parameter aggregation tool this is close to complete, though it omits return format and read-only confirmation.

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?

The tool takes zero parameters, so per the rubric the baseline is 4. There is nothing for the description to clarify beyond the schema, and it correctly adds no spurious parameter detail.

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 ('Get aggregate statistics') and resource, then enumerates the exact metrics returned (totals, breakdowns by workspace/type/tag, recently updated, orphan_rate). This is far more specific than a generic 'get stats'. It stops short of explicitly distinguishing itself from the similarly overview-oriented sibling ctx_health, so it earns a 4 rather than 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?

Gives clear when-to-use guidance: 'Use this for an overview of what is stored and to spot disconnected knowledge.' That maps the tool to two concrete scenarios. It offers no exclusions or explicit alternatives (e.g., how it differs from ctx_health or ctx_list), so it falls 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.