update_frontmatter

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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the body is preserved byte-exact, scoping the blast radius to frontmatter, and it documents the merge DSL operations. It does not mention idempotency (annotation says false) or required permissions.

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 tightly packed sentences: purpose front-loaded, then the DSL reference. Every clause earns its place with zero filler, and the higher-value scoping statement precedes the operator table.

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 a nested merge object and no output schema, the description covers the core (what changes, what is preserved, merge semantics). However, it omits expected_hash concurrency behavior, the client_id/vault roles, and any note about the return, leaving gaps an agent must guess at.

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 0% across 5 parameters, so the description must compensate. It thoroughly documents the 'merge' parameter's DSL value semantics (scalar=set, $unset, $push, $pull), which is the most complex nested field, but leaves path, vault, client_id, and expected_hash entirely undocumented.

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 ('Modify a note's frontmatter only') plus a scope constraint that separates it from write_note, which would rewrite body and frontmatter. It does not name the sibling tools it is distinct from, but the 'frontmatter only' framing makes the purpose unambiguous.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no alternatives are named (e.g. write_note, suggest_frontmatter). The 'frontmatter only' phrase is the sole implicit signal that this is for partial edits, matching the no-guidance severity seen in comparable update tools.

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