changes_since

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

With no annotations, the description carries the full burden and does so well: read-only, does not itself count as a change, counter scoped per file path, bumped on commit/undo/redo, and tokens from a prior session are deliberately treated as changed to avoid false 'unchanged'. These are exactly the behavioral traits an agent needs to use the tool safely.

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?

Purpose is front-loaded in the first sentence, then invocation, then return values, then the subtle session-id caveat. Information-dense and largely waste-free, though the final sentence is long and could be trimmed slightly.

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?

No output schema exists, so the description correctly spells out the return values (current token, modified flag, and changed-since-token indicator). Combined with the session-id caveat, an agent has everything needed to call and interpret the tool.

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 the baseline is 3, but the description goes further by explaining when to omit the token and what the token embeds (a per-plugin-load session id) with the resulting invalidation semantics. This meaningfully extends the schema's terse parameter description.

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: 'Check whether the model has changed since a previous look.' The polling/change-detection purpose is unambiguous and no sibling in the list competes with it.

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?

Explicitly tells the agent to pass the token from the previous call and to omit it on the first call, which defines the correct invocation pattern. It doesn't frame alternatives, but there is no sibling overlapping this change-detection role, so the context is clear.

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