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

Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context: the feed's last-run result explains metric staleness. It doesn't state pagination behavior, cross-workspace visibility, or ordering, so a 3 is appropriate – useful additions but not comprehensive.

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 definition then usage triggers. No wasted words, no redundancy with the title or name.

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 goes beyond a bare return-value note to describe the shape of a feed (tool called, frequency, last-run outcome) – the essential information an agent needs. Given the readOnly annotations, safety is covered; minor gaps in workspace scoping and pagination keep it from a 5.

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 the schema already defines both metricId (narrow to one) and workspace (omit to use pinned). The description implies filtering by metric and workspace through the 'which metric' framing. Baseline is 3 with high coverage; the description nudges to 4 by explaining the purpose of these filters (checking before proposing), which adds intent beyond the schema text.

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 resource ('standing instructions for how metrics' numbers arrive') and enumerates the exact contents (which tool each calls, how often, last run status). An agent can immediately distinguish it from sibling feeds tools like ledger_feeds_create, ledger_feeds_run, and ledger_feeds_preview.

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?

Provides two concrete when to use triggers: 'check before proposing a feed so you don't duplicate one' and 'consult when a user asks why a metric is stale'. This is strong contextual guidance. It stops short of describing limitations (e.g., scope, pagination) that would round it to a 5.

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