Open File In Obsidian

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

The description goes well beyond the annotations: it discloses that the tool is UI-only, does not create/modify/read file contents, returns { ok: true }, fails when the file is missing or the REST API plugin is unreachable, and may target a different vault than the filesystem session. It also notes the newPane behavior. None of this contradicts the annotations; the non-readOnlyHint is consistent with the UI state change it performs.

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?

The description is longer than the minimal case, but each block earns its place: the core behavior, the UI-only caveat, the failure modes, the vault-targeting caveat, and examples. There is minor redundancy in mentioning the Local REST API twice, but overall it is well-organized and front-loaded with the action and key parameter.

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 two-parameter tool with rich annotations and an output schema, this description is complete. It covers return values, error conditions, relationship to notes.read, interaction with vault.select, and provides examples. An agent has everything needed to invoke it correctly without consulting additional tools.

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 schema already explains both parameters. The description adds some value by clarifying the default newPane behavior ('default reuses the active pane') and providing two concrete examples, but it largely restates the schema's semantic content rather than adding substantial new meaning.

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 opens with a precise verb-resource pairing — 'Open a vault-relative note filePath in the live Obsidian UI' — and clarifies the UI scope. It explicitly distinguishes itself from notes.read by saying it does not read file contents. This is enough to separate it from siblings like notes.read and workspace.navigate.

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?

It gives a clear when-to-use signal: when you need to reveal a note in the live Obsidian UI. It also provides an explicit alternative by saying 'use notes.read for content,' and explains that vault.select does not affect this tool. It does not enumerate all sibling alternatives exhaustively, but it gives sufficient routing context for the common confusion cases.

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