Project diff

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

Beyond the readOnly/openWorld annotations, it discloses that each datum comes from "the nearest persisted point with its date and basis" — critical freshness and approximation semantics — and closes with "Never a cause," an explicit epistemic limitation on what the diff implies. These are exactly the behavioral traits an agent cannot get from structured fields.

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?

A single front-loaded sentence that answers "what does this return" before adding qualifiers, with no filler. It is dense — the enumeration of content categories plus the persistence caveat makes it long for one sentence, but each clause carries information.

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 structure, and it covers the remaining gaps an agent needs: input date format and span limit, what the payload contains, how the data is dated/approximated, and the interpretive boundary. Nothing required to call 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 only 33% (only slug is described in-schema), but the description compensates for both date parameters: it specifies the YYYY-MM-DD format and the 400-day maximum span, semantics the schema does not encode. Slug semantics remain schema-only, which is acceptable since the schema documents it.

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 with explicit scope: "what changed for this project between two dates", and enumerates the content categories (releases, status, Build Momentum, valuation/liquidity then and now). The "then and now" framing implicitly but clearly separates it from point-in-time siblings like get_project_snapshot and the sequence-based get_project_timeline.

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 one hard usage constraint (dates must be YYYY-MM-DD and at most 400 days apart), which is real guidance for constructing a valid call. However, it never says when to prefer this over get_project_snapshot or get_project_timeline, nor when-not to use it — the agent must infer the choice from the tool name.

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