Read the repo architecture digest

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

With no annotations, the description carries the full burden. It discloses that the output includes a freshness verdict and a reason (changed files), and implies a read-only operation via 'Return'. It doesn't mention edge cases like a missing digest, but the core behavior is clear.

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 with no filler. The first sentence front-loads the primary purpose and key output detail; the second adds actionable guidance. Every word 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 simple get tool, the description covers the return value and how to use it. It lacks a note about behavior when no digest exists, but this is a minor gap given the simplicity and the explicit staleness guidance.

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 has zero parameters, so the schema fully covers them. The description correctly avoids adding unnecessary parameter details, and the baseline for 0 params is 4.

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?

The description uses a specific verb ('Return') and resource ('stored architecture digest'), clearly distinguishing this tool from siblings like digest_save. It also adds what makes this tool unique: the freshness verdict that flags changed files.

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?

It explicitly tells the agent to 'Read it early' and provides a conditional follow-up ('if flagged stale, re-read the changed areas and digest_save an update'). This gives clear usage context, though it doesn't explicitly mention when not to use it or alternatives.

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