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

Adds far more than the annotations: the edit produces a new content version, existing test answers are invalidated, publication is not required, and a stale expected_content_version fails with source_read as the recovery path. This is exactly the behavioral context the destructiveHint/idempotentHint flags cannot convey, and it is consistent with them.

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 short sentences, front-loaded with the core action and precondition, then the consequences and failure mode. No filler or restatement of the tool title.

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?

For a destructive mutation with an output schema, the description covers side effects, version-conflict behavior, and recovery guidance. Nothing an agent needs before calling it 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 the baseline is 3; the description goes further by tying expected_content_version to a prior source_read, which explains its purpose rather than just its name. The name/content mapping is implied by schema titles, so no additional gain there.

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 ('Replaces a text source's title and text') plus the concurrency precondition, which cleanly separates it from siblings like source_add, source_refresh, or source_withdraw. An agent knows exactly what operation this is without opening the 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?

Gives real conditions: this is for correction (not initial creation), it takes effect on a published source without publication, and resubmitting identical text is a no-op. It does not explicitly name alternative tools (source_refresh, source_withdraw) or state when not to use it, so it stops short of the top band.

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