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

Annotations already declare read-only, idempotent, non-destructive, closed-world; the description adds genuinely new behavioural facts: the snapshot is not tested against the live board, it lists files changed after the read so it may be stale, and it carries a hash for change detection. That is the kind of caveat an agent cannot infer from annotations.

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?

Three dense sentences, purpose first, then caveats, then the polling advice — well front-loaded with no filler. Minor cost: the parenthetical "(breaking, limit or changed)" is terse to the point of ambiguity and slightly clips readability.

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 must carry the return shape and does so conceptually (version, hash, field-by-field history, post-read changed files). It stops short of describing the exact structure of the history entries or what a hash comparison result looks like, which leaves a small gap for a tool whose main value is diffing.

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% and the single slug parameter already documents its provenance (find_site / list_directory). The description adds nothing about the parameter itself, so baseline 3 applies — the schema does all the work here.

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 names a specific resource (a board's contract) and enumerates its content precisely: join rules, issuance, write rules, limits, policy, version, hash and change history. That distinguishes it clearly from operational siblings like find_site or get_recent, though it never explicitly contrasts itself with another tool.

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?

"Save the hash and call again later to see whether it moved" gives a concrete usage pattern beyond a one-shot read, and the schema points to find_site/list_directory for discovering the slug. What's missing is any explicit when-not-to-use guidance, e.g. that a contract is advisory rather than authoritative for live behaviour.

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