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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description adds real value on top: the signal is 'stored', meaning it reflects prior state and may be stale, and no new scan is triggered, so calling it is cheap and side-effect free. That is useful context annotations alone do not convey, though it says nothing about auth or failure behavior.

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?

One sentence, zero filler, with the caching behavior front-loaded as the differentiator. Every clause 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?

There is no output schema, so the description must shoulder the burden of explaining return semantics, yet 'coverage signal' is left undefined — an agent cannot tell whether it gets a percentage, a per-file breakdown, or an error when no coverage was ever imported. Adequate for a simple read, but incomplete.

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% for both parameters (context and repo_id), so the schema carries the full burden and baseline 3 applies. The description adds no additional meaning about repo_id or how the context parameter is used.

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 pairs a specific verb ('Get') with a precise resource ('the imported repository's stored coverage signal'), and the trailing clause 'without starting a new scan' implicitly separates it from scan-triggering siblings like analyze_coverage. It is clear, but it never names the sibling it contrasts with, so the differentiation is inferred rather than stated.

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?

'Without starting a new scan' signals the intended situation (cheap read of existing data) and hints at when a scan tool would be the alternative, but no sibling is named and no exclusion is explicit. Usage is implied rather than prescribed.

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