build_handoff

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

Annotations already declare readOnlyHint and destructiveHint=false, and the description's "Read-only" line restates that rather than adding to it. Where it does add real value is the compression behavior: bounded lists are cut oldest-first, budget_omitted records what was removed, and invariants/source_document_refs/approved_plan/task/reports are never truncated. That is exactly the kind of beyond-schema behavior an agent needs before choosing a budget.

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?

Front-loaded with purpose, then behavior, then the sibling comparison, with no filler sentences. The protected-versus-compressed field list is dense but every item is load-bearing; the parenthetical list of package contents is the only mildly cluttered spot.

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?

An output schema exists, so return values need not be spelled out, and the description still covers the one output concept that affects invocation (budget_exceeded). For a four-parameter read tool with full annotation and schema coverage, nothing an agent needs 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 100%, so all four parameters are already documented. The description still adds meaning by explaining the budget mechanics (roughly 3 characters per token, which parts get shortened, budget_exceeded when protected parts alone exceed the ceiling), which goes beyond the schema's phrasing.

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?

Uses a specific verb ("build") and resource ("handoff package") and enumerates the contents: shared Context, invariants, next action, task and reports. It explicitly contrasts itself with the sibling get_context, so an agent can distinguish the two without opening either schema.

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?

States the selecting condition plainly: get_context returns the same package without a budget, "so use this tool only when you need to cap its size." That is an explicit when-to-use plus a named alternative, leaving nothing to inference.

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