saved_library_delta

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

No annotations exist, so the description carries the full burden. It does disclose meaningful behavioral traits: the quota cost ('🟡 getAllPages walks + local file read') and the fact that it touches the local filesystem. However, it does not explain what happens when no snapshot exists, nor how the dry_run parameter fits a diff-only tool (dry_run implies possible mutations, which the description never addresses). It is read-only in spirit but that is implied, not stated.

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, and the quota is compressed into a single token-style line with an emoji. There is no filler. It loses one point because the second sentence's space could have carried usage guidance or behavioral clarification instead of only quota info, but overall it is efficient.

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 6-parameter tool with no annotations and no output schema, the description gives the core purpose, the snapshot provenance, and cost — a solid start. But it omits edge-case behavior (missing/corrupt snapshot), differentiation from several near-identical siblings, and any description of what the added/removed output looks like beyond the two labels. These gaps matter more because annotations and output schema carry none of the burden.

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 description coverage is 100%, so the baseline is 3 — the schema already documents all 6 parameters individually. The description adds only marginal cross-parameter context by tying snapshot_id to the backup_now backup source. It does not explain fresh_cap vs max_results tradeoffs or how type interacts with the diff scope, but the schema already covers each parameter's meaning adequately.

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 states a specific verb ('Diff'), a specific resource ('current saved tracks/albums against a local backup snapshot'), and the outcome ('added since / removed since'). It also names the snapshot source tool (backup_now), which anchors the concept and distinguishes it from playlist-snapshot or remote-state diff siblings despite the large sibling list.

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?

The phrase 'from backup_now' implies the prerequisite (a local backup must exist first), and the diff semantics imply when it applies. However, it never explicitly routes the agent away from closely related siblings such as library_snapshot_diff, diff_since_snapshot, snapshot_diff_summary, or find_new_since_snapshot, nor does it state when NOT to use it. Given the huge sibling set with overlapping snapshot-diff names, explicit exclusion would add real value.

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